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Chemical Thermodynamics Unit 14: Chemical Thermodynamics Dr. Jorge L. Alonso Miami-Dade College – Kendall Campus Textbook Reference : •Chapter # 15 (sec.12-1 •Module # 3 (sec. VIII-X CHM 1046 : General Chemistry and Qualitative Analysis

Unit 14: Chemical Thermodynamics

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CHM 1046 : General Chemistry and Qualitative Analysis. Unit 14: Chemical Thermodynamics. Dr. Jorge L. Alonso Miami-Dade College – Kendall Campus Miami, FL. Textbook Reference : Chapter # 15 (sec.12-17) Module # 3 (sec. VIII-XII). First Law of Thermodynamics. - PowerPoint PPT Presentation

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Page 1: Unit 14: Chemical Thermodynamics

ChemicalThermodynamics

Unit 14Chemical

ThermodynamicsDr Jorge L AlonsoMiami-Dade College ndash Kendall Campus

Miami FL

Textbook Reference bullChapter 15 (sec12-17)bullModule 3 (sec VIII-XII)

CHM 1046 General Chemistry and Qualitative Analysis

ChemicalThermodynamics

First Law of Thermodynamics

bull The law of conservation of energy energy cannot be created nor destroyed (James Joule in 1843 )

E = q + ww = PV

E = q + PVE = q + RT

Esys + Esurr = 0

Esys = -Esurr

bull Therefore the total energy of the universe is a constant

bull Energy can however be converted from one form to another or transferred from a system to the surroundings or vice versa

ChemicalThermodynamics

Second Law of Thermodynamics

Do all processes that loose energy occur

spontaneously (by themselves without

external influence)

First Law of ThermodynamicsStoneE1

E2

E = E2 ndash E1

Spontaneity

+ Work

- (work + heat)

ChemicalThermodynamics

Spontaneous Processesbull can proceed without any outside intervention

Spontaneity

Processes that are spontaneous in one direction

are nonspontaneous

in the reverse direction

ChemicalThermodynamics

Spontaneous Processesbull Processes that are spontaneous at one temperature

may be nonspontaneous at other temperaturesbull Above 0C it is spontaneous for ice to meltbull Below 0C the reverse process is spontaneous

Is the spontaneity of

melting ice dependent on

anything

Spontaneous T gt 0ordmC

Spontaneous T lt 0ordmC

ChemicalThermodynamics

Spontaneity

Thermodynamics vs Kinetics

C diamond C graphite

vs Speed

ChemicalThermodynamics

Stone

+ Work

Irreversible Processes

bull Heat energy is lost to dissipation and that energy will not be recoverable if the process is reversed

bull Irreversible processes cannot be undone by exactly reversing the change to the system

bull Spontaneous processes are irreversible

In a reversible process the system changes in such a way that the system and surroundings can be put back in their original states by exactly reversing the process

E1

E2

- (work + heat)

Reversible Processes

ChemicalThermodynamics

Entropy (S)

bull Entropy (S) is a term coined by Rudolph Clausius in the 1850rsquos Clausius chose S in honor of Sadi Carnot (who gave the first successful theoretical account of heat engines now known as the Carnot cycle thereby laying the foundations of the second law of thermodynamics)

bull Clausius was convinced of the significance of the ratio of heat delivered and the temperature at which it is delivered

qTEntropy (S) =

Entropy is a measure of the energy that becomes dissipated and unavailable (friction molecular motion = heat)

ChemicalThermodynamics

Entropy (S)bull Entropy can be thought of

as a measure of the randomness (disorder) of a system

bull It is related to the various modes of motion in molecules

EntropyWaterBoiling

bull Like total energy E and enthalpy H entropy is a state function

bull Therefore S = Sfinal Sinitial Solid

Liquid

GasENTROPY

ChemicalThermodynamics

Second Law of Thermodynamics

bull the entropy of the universe increases for spontaneous (irreversible) processes

bull the entropy of the universe does not change for reversible processes

Suniv = Ssystem + Ssurroundings gt 0

Suniv = Ssystem + Ssurroundings = 0

ChemicalThermodynamics

Second Law of Thermodynamics

All spontaneous processes cause the entropy of the universe to increase

ENTROPIC DOOMENTROPIC DOOM

So what is our fate as a result of the second law operating in our Universe

ChemicalThermodynamics

Entropy on the Molecular Scalebull Molecules exhibit several types of motion (Kinetic energies)

Translational Movement of a molecule from one place to another Vibrational Periodic motion of atoms within a molecule Rotational Rotation of the molecule on about an axis or rotation about

bonds

bull Boltzmann envisioned the motions of a sample of molecules at a particular instant in time This would be akin to taking a snapshot of all the

molecules He referred to this sampling as a microstate (W) of the

thermodynamic systembull Entropy is helliphellip

S = k ln Whellipwhere k is the Boltzmann constant 138 1023 JK

ChemicalThermodynamics

Entropy on the Molecular Scale

bull The number of microstates (W) and therefore the entropy (S) tends to increase with increases in which variableshellip

Temperature (T)

Volume (V)

The number of independently moving molecules ()

S = k ln Whellipwhere k is the Boltzmann constant 138 1023 JK

ChemicalThermodynamics

Entropy Changes

CaCl2 (s) Ca 2+(aq) + 2Cl-(aq)

H2O

H2O (l) H2O(g)Heat

2 H2O (l) 2 H2 (g) + O2(g)Electricity

16 CO2(g) + 18 H2O(g)2 C8H18 (l) + 25 O2 (g)

gas= 34-25 = +92 = 45 C8H18

bull In which of the following does Entropy increase amp WHYhelliphellipGases are formed from liquids and solids

Liquids or solutions are formed from solids

The number of gas molecules (or moles) increasesEntropySolutionsKMnO4(aq)

EntropyampPhaseOfMatter

bull Entropy increases with the freedom of motion of molecules

S(g) gt S(l) gt S(s)

ChemicalThermodynamics

Third Law of Thermodynamics

The entropy (S) of a pure crystalline substance at absolute zero (-273degC) is 0

ChemicalThermodynamics

Standard Entropiesbull Standard entropies tend to increase with increasing

molar mass

bull Larger and more complex molecules have greater entropies (greater ways to execute molecular motions)

EntropyampMolecuarSize EntropyampTempC7H15 500 K S=921JnK vs 200 K

ChemicalThermodynamics

Absolute Entropy (S)

- 237degC (0 K) S = 0

Standard Entropy (S˚)

25degC (298 K) S =

dT298

0 TC

T

TCS

K 298T

0T

TTC

TTmc

T

q S

Calculate the sum of all the infinitesimally small changes in entropy as T varies from T=0 T= 298 by taking its Integral

Standard Entropies (298 K) from Absolute Entropies (0K)

Sdeg

Temp (K)

Solid Liquid Gas

Hdegfus

Hdegvap

q = mcT

q = mcT

q = mcT

298

S

ChemicalThermodynamics

Entropy Changes in the System

where n and m are the coefficients in the balanced chemical equation

oreactants

oproducts

o298 SmSnS

Sdegsyst = Sdegrxn T

Entropy changes for a reaction (= system) can be estimated in a manner analogous to that by which H is estimated

ChemicalThermodynamics

Problem Calculate the standard entropy changes for the following reaction at 25oC

N2 (g) + 3 H2 (g) 2 NH3 (g)

Sdeg = nSdeg(prod) - mSdeg(react)

Sdeg = - 1983 J

2(1925) ndash [(1915)+3(1306)]

Entropy Changes in the System

ChemicalThermodynamics

oreactants

oproducts

o298 S S S

Thermodynamic Changes in Systems (Chem Reactions)

Appendix 1 (CHM 1046 Module) notice Sdeg is in J not kJ

Grxn = Gf (products) Gf (reactants)

Hrxn = Hf (products) - Hf (reactants)

ChemicalThermodynamics

Entropy Changes in the Surroundings

bull Heat (q) that flows into or out of the system changes the entropy of the surroundings

Ssurr prop - (qsys)bull For an isothermal process

Ssurr= (qsys)T

bull At constant pressure qsys is simply H for the system

System

q

q

qq

q

q

q

Ssurr= Hsys

TSurroundings

What in a chemical reaction causes entropy changes in the surroundings

ChemicalThermodynamics

Entropy Change in the Universe

K 298

1000 692( kJ) Jxmol kJ

Problem Calculate the Suniv for the synthesis of ammonia 25oC

N2 (g) + 3 H2 (g) 2 NH3 (g) Hdegrxn = - 926 kJmol

Ssurr =-Hsys

T

Ssurr = 311 JKmol

Suniv = Ssyst or rxn + Ssurr

nS(prod) - mS(react)

Sdegsyst = - 199 JKmiddotmol

2(1925) ndash [(1915)+3(1306)]

Suniv = - 1983 JKmiddotmol + 311 JKmol

Suniv = 113 JKmol

ChemicalThermodynamics

Entropy Change in the Universe

bull ThenSuniv = Ssyst + Hsystem

T

Suniv = Ssyst or rxn + Ssurr

Ssurr =-Hsys

Tbull Since

TSuniv = Hsyst TSsyst

TSuniv is defined as the Gibbs (free) Energy G

TSuniv = TSsyst + Hsyst

J Willard Gibbs USA 1839-1903

Multiplying both sides by T

ChemicalThermodynamics

bull When Suniv is positive G is negative

bull When G is negative the process is spontaneous

Gibbs Free Energy (G)

Gibbs Energy (-TΔS) measures the useful or process-initiating work obtainable from an isothermal isobaric thermodynamic system Technically the Gibbs free energy is the maximum amount of non-expansion work which can be extracted from a closed system or this maximum can be attained only in a completely reversible process

Guniv = Hsys TSsysTSuniv =

ChemicalThermodynamics

Free Energy Changes

At temperatures other than 25degC

Gdeg = H TS

How does G change with temperature

bull There are two parts to the free energy equation Hmdash the enthalpy term TS mdash the entropy term

bull The temperature dependence of free energy then comes from the entropy term

ChemicalThermodynamics

Spontaneity Enthalpy amp Entropy

Gdeg = H TS

Spontaneous all T

NonSpontaneous all T

Spontaneous high TSpontaneous low T

ChemicalThermodynamics

Spontaneity Enthalpy amp Entropy

Entropy Driven Reactions

Entropy amp Enthalpy Driven Reaction

Enthalpy Driven Reaction

Na2CO3(s) + HCl(aq) NaCl(aq) + CO2 (g)

2 H2(g) + O2 (g) 2 H2O(g)

NH4NO3(s) NH4+

(aq) + NO3-(aq)

n = 2-3 = -1

S = +H = +

G = H( TS)

EntropySyst+SurrFormationOfWater

(-TS)

(-TS)

(+TS)H = - S = -

H = - S = +

Enthalpy EntropyH2O

ChemicalThermodynamics

ProblemsGdeg = HT(S)

(-763)

ndash (-804)

+41

(3549)

ndash (2219)

+1330

Gdeg = H TS = (1313kJ) T(133kJ)

T = 987

TiCl4(l) TiCl4(g)

(-T)Reactant

Product

ChemicalThermodynamics

Standard Free Energy Changes

Analogous to standard enthalpies of formation are standard free energies of formation G

f

G = nG(products) mGf (reactants)f

where n and m are the stoichiometric coefficients

ChemicalThermodynamics

Standard Free Energy Changes

12 CO2(g) + 6 H2O(g)2 C6H6 (l) + 15 O2 (g)

Grxn = nG(prod) mG(react)f

Calculate the standard free energy changes for the above reaction 25 degC

f

[12(-394) + 6(-229)] ndash [2(125) + 15 (0)]

ndash [2 C6H6 (l) + 15 O2(g)][12 CO2(g) + 6 H2O(g)]

Grxn = - 6352 Jmol K

Standard Molar Gibbs Energy of Formation (Gdegf)

CO2 (g) -394

H2O (g) -229

C6H6 (l) 125

ChemicalThermodynamics

Fourth Law of Thermodynamics EmergenceComplex emergent systems spontaneously (-G) arise when energy flows through a collection of many interacting particles resulting in new patterns of complex behaviors that are much more than the sum of the individual parts (+S)

The formation of these complex patterns in emergent systems is more efficient in the dissipation of energy (-H) thus speeds up the increase of entropy in the universe

G = H -TSA precise definition of emergence and a useful mathematical formulation of this phenomenon remains elusive

C f [n i E(t)]Examples cells forming living organisms stars forming galaxies neurons forming conscious brain

ChemicalThermodynamics

ChemicalThermodynamics

ChemicalThermodynamics

ChemicalThermodynamics

ChemicalThermodynamics

ChemicalThermodynamics

ChemicalThermodynamics

2002 B

ChemicalThermodynamics

ChemicalThermodynamics

ChemicalThermodynamics

2003 A

ChemicalThermodynamics

ChemicalThermodynamics

2004 A

ChemicalThermodynamics

ChemicalThermodynamics

ChemicalThermodynamics

2004 B

ChemicalThermodynamics

ChemicalThermodynamics

2005 A

ChemicalThermodynamics

ChemicalThermodynamics

2006 (B)

ChemicalThermodynamics

ChemicalThermodynamics

ChemicalThermodynamics

2007 (A)

ChemicalThermodynamics

ChemicalThermodynamics

  • Unit 14 Chemical Thermodynamics
  • First Law of Thermodynamics
  • Second Law of Thermodynamics
  • Spontaneous Processes
  • Slide 5
  • Spontaneity
  • Irreversible Processes
  • Entropy (S)
  • Slide 9
  • Second Law of Thermodynamics
  • Slide 11
  • Entropy on the Molecular Scale
  • Slide 13
  • Entropy Changes
  • Third Law of Thermodynamics
  • Standard Entropies
  • Standard Entropies (298 K) from Absolute Entropies (0K)
  • Entropy Changes in the System
  • Slide 19
  • Thermodynamic Changes in Systems (Chem Reactions)
  • Entropy Changes in the Surroundings
  • Entropy Change in the Universe
  • Slide 23
  • Gibbs Free Energy (G)
  • Free Energy Changes
  • Spontaneity Enthalpy amp Entropy
  • Slide 27
  • Problems
  • Standard Free Energy Changes
  • Slide 30
  • Fourth Law of Thermodynamics Emergence
  • Slide 32
  • Slide 33
  • Slide 34
  • Slide 35
  • Slide 36
  • Slide 37
  • Slide 38
  • Slide 39
  • Slide 40
  • Slide 41
  • Slide 42
  • Slide 43
  • Slide 44
  • Slide 45
  • Slide 46
  • Slide 47
  • Slide 48
  • Slide 49
  • 2006 (B)
  • Slide 51
  • Slide 52
  • Slide 53
  • Slide 54
  • Slide 55
Page 2: Unit 14: Chemical Thermodynamics

ChemicalThermodynamics

First Law of Thermodynamics

bull The law of conservation of energy energy cannot be created nor destroyed (James Joule in 1843 )

E = q + ww = PV

E = q + PVE = q + RT

Esys + Esurr = 0

Esys = -Esurr

bull Therefore the total energy of the universe is a constant

bull Energy can however be converted from one form to another or transferred from a system to the surroundings or vice versa

ChemicalThermodynamics

Second Law of Thermodynamics

Do all processes that loose energy occur

spontaneously (by themselves without

external influence)

First Law of ThermodynamicsStoneE1

E2

E = E2 ndash E1

Spontaneity

+ Work

- (work + heat)

ChemicalThermodynamics

Spontaneous Processesbull can proceed without any outside intervention

Spontaneity

Processes that are spontaneous in one direction

are nonspontaneous

in the reverse direction

ChemicalThermodynamics

Spontaneous Processesbull Processes that are spontaneous at one temperature

may be nonspontaneous at other temperaturesbull Above 0C it is spontaneous for ice to meltbull Below 0C the reverse process is spontaneous

Is the spontaneity of

melting ice dependent on

anything

Spontaneous T gt 0ordmC

Spontaneous T lt 0ordmC

ChemicalThermodynamics

Spontaneity

Thermodynamics vs Kinetics

C diamond C graphite

vs Speed

ChemicalThermodynamics

Stone

+ Work

Irreversible Processes

bull Heat energy is lost to dissipation and that energy will not be recoverable if the process is reversed

bull Irreversible processes cannot be undone by exactly reversing the change to the system

bull Spontaneous processes are irreversible

In a reversible process the system changes in such a way that the system and surroundings can be put back in their original states by exactly reversing the process

E1

E2

- (work + heat)

Reversible Processes

ChemicalThermodynamics

Entropy (S)

bull Entropy (S) is a term coined by Rudolph Clausius in the 1850rsquos Clausius chose S in honor of Sadi Carnot (who gave the first successful theoretical account of heat engines now known as the Carnot cycle thereby laying the foundations of the second law of thermodynamics)

bull Clausius was convinced of the significance of the ratio of heat delivered and the temperature at which it is delivered

qTEntropy (S) =

Entropy is a measure of the energy that becomes dissipated and unavailable (friction molecular motion = heat)

ChemicalThermodynamics

Entropy (S)bull Entropy can be thought of

as a measure of the randomness (disorder) of a system

bull It is related to the various modes of motion in molecules

EntropyWaterBoiling

bull Like total energy E and enthalpy H entropy is a state function

bull Therefore S = Sfinal Sinitial Solid

Liquid

GasENTROPY

ChemicalThermodynamics

Second Law of Thermodynamics

bull the entropy of the universe increases for spontaneous (irreversible) processes

bull the entropy of the universe does not change for reversible processes

Suniv = Ssystem + Ssurroundings gt 0

Suniv = Ssystem + Ssurroundings = 0

ChemicalThermodynamics

Second Law of Thermodynamics

All spontaneous processes cause the entropy of the universe to increase

ENTROPIC DOOMENTROPIC DOOM

So what is our fate as a result of the second law operating in our Universe

ChemicalThermodynamics

Entropy on the Molecular Scalebull Molecules exhibit several types of motion (Kinetic energies)

Translational Movement of a molecule from one place to another Vibrational Periodic motion of atoms within a molecule Rotational Rotation of the molecule on about an axis or rotation about

bonds

bull Boltzmann envisioned the motions of a sample of molecules at a particular instant in time This would be akin to taking a snapshot of all the

molecules He referred to this sampling as a microstate (W) of the

thermodynamic systembull Entropy is helliphellip

S = k ln Whellipwhere k is the Boltzmann constant 138 1023 JK

ChemicalThermodynamics

Entropy on the Molecular Scale

bull The number of microstates (W) and therefore the entropy (S) tends to increase with increases in which variableshellip

Temperature (T)

Volume (V)

The number of independently moving molecules ()

S = k ln Whellipwhere k is the Boltzmann constant 138 1023 JK

ChemicalThermodynamics

Entropy Changes

CaCl2 (s) Ca 2+(aq) + 2Cl-(aq)

H2O

H2O (l) H2O(g)Heat

2 H2O (l) 2 H2 (g) + O2(g)Electricity

16 CO2(g) + 18 H2O(g)2 C8H18 (l) + 25 O2 (g)

gas= 34-25 = +92 = 45 C8H18

bull In which of the following does Entropy increase amp WHYhelliphellipGases are formed from liquids and solids

Liquids or solutions are formed from solids

The number of gas molecules (or moles) increasesEntropySolutionsKMnO4(aq)

EntropyampPhaseOfMatter

bull Entropy increases with the freedom of motion of molecules

S(g) gt S(l) gt S(s)

ChemicalThermodynamics

Third Law of Thermodynamics

The entropy (S) of a pure crystalline substance at absolute zero (-273degC) is 0

ChemicalThermodynamics

Standard Entropiesbull Standard entropies tend to increase with increasing

molar mass

bull Larger and more complex molecules have greater entropies (greater ways to execute molecular motions)

EntropyampMolecuarSize EntropyampTempC7H15 500 K S=921JnK vs 200 K

ChemicalThermodynamics

Absolute Entropy (S)

- 237degC (0 K) S = 0

Standard Entropy (S˚)

25degC (298 K) S =

dT298

0 TC

T

TCS

K 298T

0T

TTC

TTmc

T

q S

Calculate the sum of all the infinitesimally small changes in entropy as T varies from T=0 T= 298 by taking its Integral

Standard Entropies (298 K) from Absolute Entropies (0K)

Sdeg

Temp (K)

Solid Liquid Gas

Hdegfus

Hdegvap

q = mcT

q = mcT

q = mcT

298

S

ChemicalThermodynamics

Entropy Changes in the System

where n and m are the coefficients in the balanced chemical equation

oreactants

oproducts

o298 SmSnS

Sdegsyst = Sdegrxn T

Entropy changes for a reaction (= system) can be estimated in a manner analogous to that by which H is estimated

ChemicalThermodynamics

Problem Calculate the standard entropy changes for the following reaction at 25oC

N2 (g) + 3 H2 (g) 2 NH3 (g)

Sdeg = nSdeg(prod) - mSdeg(react)

Sdeg = - 1983 J

2(1925) ndash [(1915)+3(1306)]

Entropy Changes in the System

ChemicalThermodynamics

oreactants

oproducts

o298 S S S

Thermodynamic Changes in Systems (Chem Reactions)

Appendix 1 (CHM 1046 Module) notice Sdeg is in J not kJ

Grxn = Gf (products) Gf (reactants)

Hrxn = Hf (products) - Hf (reactants)

ChemicalThermodynamics

Entropy Changes in the Surroundings

bull Heat (q) that flows into or out of the system changes the entropy of the surroundings

Ssurr prop - (qsys)bull For an isothermal process

Ssurr= (qsys)T

bull At constant pressure qsys is simply H for the system

System

q

q

qq

q

q

q

Ssurr= Hsys

TSurroundings

What in a chemical reaction causes entropy changes in the surroundings

ChemicalThermodynamics

Entropy Change in the Universe

K 298

1000 692( kJ) Jxmol kJ

Problem Calculate the Suniv for the synthesis of ammonia 25oC

N2 (g) + 3 H2 (g) 2 NH3 (g) Hdegrxn = - 926 kJmol

Ssurr =-Hsys

T

Ssurr = 311 JKmol

Suniv = Ssyst or rxn + Ssurr

nS(prod) - mS(react)

Sdegsyst = - 199 JKmiddotmol

2(1925) ndash [(1915)+3(1306)]

Suniv = - 1983 JKmiddotmol + 311 JKmol

Suniv = 113 JKmol

ChemicalThermodynamics

Entropy Change in the Universe

bull ThenSuniv = Ssyst + Hsystem

T

Suniv = Ssyst or rxn + Ssurr

Ssurr =-Hsys

Tbull Since

TSuniv = Hsyst TSsyst

TSuniv is defined as the Gibbs (free) Energy G

TSuniv = TSsyst + Hsyst

J Willard Gibbs USA 1839-1903

Multiplying both sides by T

ChemicalThermodynamics

bull When Suniv is positive G is negative

bull When G is negative the process is spontaneous

Gibbs Free Energy (G)

Gibbs Energy (-TΔS) measures the useful or process-initiating work obtainable from an isothermal isobaric thermodynamic system Technically the Gibbs free energy is the maximum amount of non-expansion work which can be extracted from a closed system or this maximum can be attained only in a completely reversible process

Guniv = Hsys TSsysTSuniv =

ChemicalThermodynamics

Free Energy Changes

At temperatures other than 25degC

Gdeg = H TS

How does G change with temperature

bull There are two parts to the free energy equation Hmdash the enthalpy term TS mdash the entropy term

bull The temperature dependence of free energy then comes from the entropy term

ChemicalThermodynamics

Spontaneity Enthalpy amp Entropy

Gdeg = H TS

Spontaneous all T

NonSpontaneous all T

Spontaneous high TSpontaneous low T

ChemicalThermodynamics

Spontaneity Enthalpy amp Entropy

Entropy Driven Reactions

Entropy amp Enthalpy Driven Reaction

Enthalpy Driven Reaction

Na2CO3(s) + HCl(aq) NaCl(aq) + CO2 (g)

2 H2(g) + O2 (g) 2 H2O(g)

NH4NO3(s) NH4+

(aq) + NO3-(aq)

n = 2-3 = -1

S = +H = +

G = H( TS)

EntropySyst+SurrFormationOfWater

(-TS)

(-TS)

(+TS)H = - S = -

H = - S = +

Enthalpy EntropyH2O

ChemicalThermodynamics

ProblemsGdeg = HT(S)

(-763)

ndash (-804)

+41

(3549)

ndash (2219)

+1330

Gdeg = H TS = (1313kJ) T(133kJ)

T = 987

TiCl4(l) TiCl4(g)

(-T)Reactant

Product

ChemicalThermodynamics

Standard Free Energy Changes

Analogous to standard enthalpies of formation are standard free energies of formation G

f

G = nG(products) mGf (reactants)f

where n and m are the stoichiometric coefficients

ChemicalThermodynamics

Standard Free Energy Changes

12 CO2(g) + 6 H2O(g)2 C6H6 (l) + 15 O2 (g)

Grxn = nG(prod) mG(react)f

Calculate the standard free energy changes for the above reaction 25 degC

f

[12(-394) + 6(-229)] ndash [2(125) + 15 (0)]

ndash [2 C6H6 (l) + 15 O2(g)][12 CO2(g) + 6 H2O(g)]

Grxn = - 6352 Jmol K

Standard Molar Gibbs Energy of Formation (Gdegf)

CO2 (g) -394

H2O (g) -229

C6H6 (l) 125

ChemicalThermodynamics

Fourth Law of Thermodynamics EmergenceComplex emergent systems spontaneously (-G) arise when energy flows through a collection of many interacting particles resulting in new patterns of complex behaviors that are much more than the sum of the individual parts (+S)

The formation of these complex patterns in emergent systems is more efficient in the dissipation of energy (-H) thus speeds up the increase of entropy in the universe

G = H -TSA precise definition of emergence and a useful mathematical formulation of this phenomenon remains elusive

C f [n i E(t)]Examples cells forming living organisms stars forming galaxies neurons forming conscious brain

ChemicalThermodynamics

ChemicalThermodynamics

ChemicalThermodynamics

ChemicalThermodynamics

ChemicalThermodynamics

ChemicalThermodynamics

ChemicalThermodynamics

2002 B

ChemicalThermodynamics

ChemicalThermodynamics

ChemicalThermodynamics

2003 A

ChemicalThermodynamics

ChemicalThermodynamics

2004 A

ChemicalThermodynamics

ChemicalThermodynamics

ChemicalThermodynamics

2004 B

ChemicalThermodynamics

ChemicalThermodynamics

2005 A

ChemicalThermodynamics

ChemicalThermodynamics

2006 (B)

ChemicalThermodynamics

ChemicalThermodynamics

ChemicalThermodynamics

2007 (A)

ChemicalThermodynamics

ChemicalThermodynamics

  • Unit 14 Chemical Thermodynamics
  • First Law of Thermodynamics
  • Second Law of Thermodynamics
  • Spontaneous Processes
  • Slide 5
  • Spontaneity
  • Irreversible Processes
  • Entropy (S)
  • Slide 9
  • Second Law of Thermodynamics
  • Slide 11
  • Entropy on the Molecular Scale
  • Slide 13
  • Entropy Changes
  • Third Law of Thermodynamics
  • Standard Entropies
  • Standard Entropies (298 K) from Absolute Entropies (0K)
  • Entropy Changes in the System
  • Slide 19
  • Thermodynamic Changes in Systems (Chem Reactions)
  • Entropy Changes in the Surroundings
  • Entropy Change in the Universe
  • Slide 23
  • Gibbs Free Energy (G)
  • Free Energy Changes
  • Spontaneity Enthalpy amp Entropy
  • Slide 27
  • Problems
  • Standard Free Energy Changes
  • Slide 30
  • Fourth Law of Thermodynamics Emergence
  • Slide 32
  • Slide 33
  • Slide 34
  • Slide 35
  • Slide 36
  • Slide 37
  • Slide 38
  • Slide 39
  • Slide 40
  • Slide 41
  • Slide 42
  • Slide 43
  • Slide 44
  • Slide 45
  • Slide 46
  • Slide 47
  • Slide 48
  • Slide 49
  • 2006 (B)
  • Slide 51
  • Slide 52
  • Slide 53
  • Slide 54
  • Slide 55
Page 3: Unit 14: Chemical Thermodynamics

ChemicalThermodynamics

Second Law of Thermodynamics

Do all processes that loose energy occur

spontaneously (by themselves without

external influence)

First Law of ThermodynamicsStoneE1

E2

E = E2 ndash E1

Spontaneity

+ Work

- (work + heat)

ChemicalThermodynamics

Spontaneous Processesbull can proceed without any outside intervention

Spontaneity

Processes that are spontaneous in one direction

are nonspontaneous

in the reverse direction

ChemicalThermodynamics

Spontaneous Processesbull Processes that are spontaneous at one temperature

may be nonspontaneous at other temperaturesbull Above 0C it is spontaneous for ice to meltbull Below 0C the reverse process is spontaneous

Is the spontaneity of

melting ice dependent on

anything

Spontaneous T gt 0ordmC

Spontaneous T lt 0ordmC

ChemicalThermodynamics

Spontaneity

Thermodynamics vs Kinetics

C diamond C graphite

vs Speed

ChemicalThermodynamics

Stone

+ Work

Irreversible Processes

bull Heat energy is lost to dissipation and that energy will not be recoverable if the process is reversed

bull Irreversible processes cannot be undone by exactly reversing the change to the system

bull Spontaneous processes are irreversible

In a reversible process the system changes in such a way that the system and surroundings can be put back in their original states by exactly reversing the process

E1

E2

- (work + heat)

Reversible Processes

ChemicalThermodynamics

Entropy (S)

bull Entropy (S) is a term coined by Rudolph Clausius in the 1850rsquos Clausius chose S in honor of Sadi Carnot (who gave the first successful theoretical account of heat engines now known as the Carnot cycle thereby laying the foundations of the second law of thermodynamics)

bull Clausius was convinced of the significance of the ratio of heat delivered and the temperature at which it is delivered

qTEntropy (S) =

Entropy is a measure of the energy that becomes dissipated and unavailable (friction molecular motion = heat)

ChemicalThermodynamics

Entropy (S)bull Entropy can be thought of

as a measure of the randomness (disorder) of a system

bull It is related to the various modes of motion in molecules

EntropyWaterBoiling

bull Like total energy E and enthalpy H entropy is a state function

bull Therefore S = Sfinal Sinitial Solid

Liquid

GasENTROPY

ChemicalThermodynamics

Second Law of Thermodynamics

bull the entropy of the universe increases for spontaneous (irreversible) processes

bull the entropy of the universe does not change for reversible processes

Suniv = Ssystem + Ssurroundings gt 0

Suniv = Ssystem + Ssurroundings = 0

ChemicalThermodynamics

Second Law of Thermodynamics

All spontaneous processes cause the entropy of the universe to increase

ENTROPIC DOOMENTROPIC DOOM

So what is our fate as a result of the second law operating in our Universe

ChemicalThermodynamics

Entropy on the Molecular Scalebull Molecules exhibit several types of motion (Kinetic energies)

Translational Movement of a molecule from one place to another Vibrational Periodic motion of atoms within a molecule Rotational Rotation of the molecule on about an axis or rotation about

bonds

bull Boltzmann envisioned the motions of a sample of molecules at a particular instant in time This would be akin to taking a snapshot of all the

molecules He referred to this sampling as a microstate (W) of the

thermodynamic systembull Entropy is helliphellip

S = k ln Whellipwhere k is the Boltzmann constant 138 1023 JK

ChemicalThermodynamics

Entropy on the Molecular Scale

bull The number of microstates (W) and therefore the entropy (S) tends to increase with increases in which variableshellip

Temperature (T)

Volume (V)

The number of independently moving molecules ()

S = k ln Whellipwhere k is the Boltzmann constant 138 1023 JK

ChemicalThermodynamics

Entropy Changes

CaCl2 (s) Ca 2+(aq) + 2Cl-(aq)

H2O

H2O (l) H2O(g)Heat

2 H2O (l) 2 H2 (g) + O2(g)Electricity

16 CO2(g) + 18 H2O(g)2 C8H18 (l) + 25 O2 (g)

gas= 34-25 = +92 = 45 C8H18

bull In which of the following does Entropy increase amp WHYhelliphellipGases are formed from liquids and solids

Liquids or solutions are formed from solids

The number of gas molecules (or moles) increasesEntropySolutionsKMnO4(aq)

EntropyampPhaseOfMatter

bull Entropy increases with the freedom of motion of molecules

S(g) gt S(l) gt S(s)

ChemicalThermodynamics

Third Law of Thermodynamics

The entropy (S) of a pure crystalline substance at absolute zero (-273degC) is 0

ChemicalThermodynamics

Standard Entropiesbull Standard entropies tend to increase with increasing

molar mass

bull Larger and more complex molecules have greater entropies (greater ways to execute molecular motions)

EntropyampMolecuarSize EntropyampTempC7H15 500 K S=921JnK vs 200 K

ChemicalThermodynamics

Absolute Entropy (S)

- 237degC (0 K) S = 0

Standard Entropy (S˚)

25degC (298 K) S =

dT298

0 TC

T

TCS

K 298T

0T

TTC

TTmc

T

q S

Calculate the sum of all the infinitesimally small changes in entropy as T varies from T=0 T= 298 by taking its Integral

Standard Entropies (298 K) from Absolute Entropies (0K)

Sdeg

Temp (K)

Solid Liquid Gas

Hdegfus

Hdegvap

q = mcT

q = mcT

q = mcT

298

S

ChemicalThermodynamics

Entropy Changes in the System

where n and m are the coefficients in the balanced chemical equation

oreactants

oproducts

o298 SmSnS

Sdegsyst = Sdegrxn T

Entropy changes for a reaction (= system) can be estimated in a manner analogous to that by which H is estimated

ChemicalThermodynamics

Problem Calculate the standard entropy changes for the following reaction at 25oC

N2 (g) + 3 H2 (g) 2 NH3 (g)

Sdeg = nSdeg(prod) - mSdeg(react)

Sdeg = - 1983 J

2(1925) ndash [(1915)+3(1306)]

Entropy Changes in the System

ChemicalThermodynamics

oreactants

oproducts

o298 S S S

Thermodynamic Changes in Systems (Chem Reactions)

Appendix 1 (CHM 1046 Module) notice Sdeg is in J not kJ

Grxn = Gf (products) Gf (reactants)

Hrxn = Hf (products) - Hf (reactants)

ChemicalThermodynamics

Entropy Changes in the Surroundings

bull Heat (q) that flows into or out of the system changes the entropy of the surroundings

Ssurr prop - (qsys)bull For an isothermal process

Ssurr= (qsys)T

bull At constant pressure qsys is simply H for the system

System

q

q

qq

q

q

q

Ssurr= Hsys

TSurroundings

What in a chemical reaction causes entropy changes in the surroundings

ChemicalThermodynamics

Entropy Change in the Universe

K 298

1000 692( kJ) Jxmol kJ

Problem Calculate the Suniv for the synthesis of ammonia 25oC

N2 (g) + 3 H2 (g) 2 NH3 (g) Hdegrxn = - 926 kJmol

Ssurr =-Hsys

T

Ssurr = 311 JKmol

Suniv = Ssyst or rxn + Ssurr

nS(prod) - mS(react)

Sdegsyst = - 199 JKmiddotmol

2(1925) ndash [(1915)+3(1306)]

Suniv = - 1983 JKmiddotmol + 311 JKmol

Suniv = 113 JKmol

ChemicalThermodynamics

Entropy Change in the Universe

bull ThenSuniv = Ssyst + Hsystem

T

Suniv = Ssyst or rxn + Ssurr

Ssurr =-Hsys

Tbull Since

TSuniv = Hsyst TSsyst

TSuniv is defined as the Gibbs (free) Energy G

TSuniv = TSsyst + Hsyst

J Willard Gibbs USA 1839-1903

Multiplying both sides by T

ChemicalThermodynamics

bull When Suniv is positive G is negative

bull When G is negative the process is spontaneous

Gibbs Free Energy (G)

Gibbs Energy (-TΔS) measures the useful or process-initiating work obtainable from an isothermal isobaric thermodynamic system Technically the Gibbs free energy is the maximum amount of non-expansion work which can be extracted from a closed system or this maximum can be attained only in a completely reversible process

Guniv = Hsys TSsysTSuniv =

ChemicalThermodynamics

Free Energy Changes

At temperatures other than 25degC

Gdeg = H TS

How does G change with temperature

bull There are two parts to the free energy equation Hmdash the enthalpy term TS mdash the entropy term

bull The temperature dependence of free energy then comes from the entropy term

ChemicalThermodynamics

Spontaneity Enthalpy amp Entropy

Gdeg = H TS

Spontaneous all T

NonSpontaneous all T

Spontaneous high TSpontaneous low T

ChemicalThermodynamics

Spontaneity Enthalpy amp Entropy

Entropy Driven Reactions

Entropy amp Enthalpy Driven Reaction

Enthalpy Driven Reaction

Na2CO3(s) + HCl(aq) NaCl(aq) + CO2 (g)

2 H2(g) + O2 (g) 2 H2O(g)

NH4NO3(s) NH4+

(aq) + NO3-(aq)

n = 2-3 = -1

S = +H = +

G = H( TS)

EntropySyst+SurrFormationOfWater

(-TS)

(-TS)

(+TS)H = - S = -

H = - S = +

Enthalpy EntropyH2O

ChemicalThermodynamics

ProblemsGdeg = HT(S)

(-763)

ndash (-804)

+41

(3549)

ndash (2219)

+1330

Gdeg = H TS = (1313kJ) T(133kJ)

T = 987

TiCl4(l) TiCl4(g)

(-T)Reactant

Product

ChemicalThermodynamics

Standard Free Energy Changes

Analogous to standard enthalpies of formation are standard free energies of formation G

f

G = nG(products) mGf (reactants)f

where n and m are the stoichiometric coefficients

ChemicalThermodynamics

Standard Free Energy Changes

12 CO2(g) + 6 H2O(g)2 C6H6 (l) + 15 O2 (g)

Grxn = nG(prod) mG(react)f

Calculate the standard free energy changes for the above reaction 25 degC

f

[12(-394) + 6(-229)] ndash [2(125) + 15 (0)]

ndash [2 C6H6 (l) + 15 O2(g)][12 CO2(g) + 6 H2O(g)]

Grxn = - 6352 Jmol K

Standard Molar Gibbs Energy of Formation (Gdegf)

CO2 (g) -394

H2O (g) -229

C6H6 (l) 125

ChemicalThermodynamics

Fourth Law of Thermodynamics EmergenceComplex emergent systems spontaneously (-G) arise when energy flows through a collection of many interacting particles resulting in new patterns of complex behaviors that are much more than the sum of the individual parts (+S)

The formation of these complex patterns in emergent systems is more efficient in the dissipation of energy (-H) thus speeds up the increase of entropy in the universe

G = H -TSA precise definition of emergence and a useful mathematical formulation of this phenomenon remains elusive

C f [n i E(t)]Examples cells forming living organisms stars forming galaxies neurons forming conscious brain

ChemicalThermodynamics

ChemicalThermodynamics

ChemicalThermodynamics

ChemicalThermodynamics

ChemicalThermodynamics

ChemicalThermodynamics

ChemicalThermodynamics

2002 B

ChemicalThermodynamics

ChemicalThermodynamics

ChemicalThermodynamics

2003 A

ChemicalThermodynamics

ChemicalThermodynamics

2004 A

ChemicalThermodynamics

ChemicalThermodynamics

ChemicalThermodynamics

2004 B

ChemicalThermodynamics

ChemicalThermodynamics

2005 A

ChemicalThermodynamics

ChemicalThermodynamics

2006 (B)

ChemicalThermodynamics

ChemicalThermodynamics

ChemicalThermodynamics

2007 (A)

ChemicalThermodynamics

ChemicalThermodynamics

  • Unit 14 Chemical Thermodynamics
  • First Law of Thermodynamics
  • Second Law of Thermodynamics
  • Spontaneous Processes
  • Slide 5
  • Spontaneity
  • Irreversible Processes
  • Entropy (S)
  • Slide 9
  • Second Law of Thermodynamics
  • Slide 11
  • Entropy on the Molecular Scale
  • Slide 13
  • Entropy Changes
  • Third Law of Thermodynamics
  • Standard Entropies
  • Standard Entropies (298 K) from Absolute Entropies (0K)
  • Entropy Changes in the System
  • Slide 19
  • Thermodynamic Changes in Systems (Chem Reactions)
  • Entropy Changes in the Surroundings
  • Entropy Change in the Universe
  • Slide 23
  • Gibbs Free Energy (G)
  • Free Energy Changes
  • Spontaneity Enthalpy amp Entropy
  • Slide 27
  • Problems
  • Standard Free Energy Changes
  • Slide 30
  • Fourth Law of Thermodynamics Emergence
  • Slide 32
  • Slide 33
  • Slide 34
  • Slide 35
  • Slide 36
  • Slide 37
  • Slide 38
  • Slide 39
  • Slide 40
  • Slide 41
  • Slide 42
  • Slide 43
  • Slide 44
  • Slide 45
  • Slide 46
  • Slide 47
  • Slide 48
  • Slide 49
  • 2006 (B)
  • Slide 51
  • Slide 52
  • Slide 53
  • Slide 54
  • Slide 55
Page 4: Unit 14: Chemical Thermodynamics

ChemicalThermodynamics

Spontaneous Processesbull can proceed without any outside intervention

Spontaneity

Processes that are spontaneous in one direction

are nonspontaneous

in the reverse direction

ChemicalThermodynamics

Spontaneous Processesbull Processes that are spontaneous at one temperature

may be nonspontaneous at other temperaturesbull Above 0C it is spontaneous for ice to meltbull Below 0C the reverse process is spontaneous

Is the spontaneity of

melting ice dependent on

anything

Spontaneous T gt 0ordmC

Spontaneous T lt 0ordmC

ChemicalThermodynamics

Spontaneity

Thermodynamics vs Kinetics

C diamond C graphite

vs Speed

ChemicalThermodynamics

Stone

+ Work

Irreversible Processes

bull Heat energy is lost to dissipation and that energy will not be recoverable if the process is reversed

bull Irreversible processes cannot be undone by exactly reversing the change to the system

bull Spontaneous processes are irreversible

In a reversible process the system changes in such a way that the system and surroundings can be put back in their original states by exactly reversing the process

E1

E2

- (work + heat)

Reversible Processes

ChemicalThermodynamics

Entropy (S)

bull Entropy (S) is a term coined by Rudolph Clausius in the 1850rsquos Clausius chose S in honor of Sadi Carnot (who gave the first successful theoretical account of heat engines now known as the Carnot cycle thereby laying the foundations of the second law of thermodynamics)

bull Clausius was convinced of the significance of the ratio of heat delivered and the temperature at which it is delivered

qTEntropy (S) =

Entropy is a measure of the energy that becomes dissipated and unavailable (friction molecular motion = heat)

ChemicalThermodynamics

Entropy (S)bull Entropy can be thought of

as a measure of the randomness (disorder) of a system

bull It is related to the various modes of motion in molecules

EntropyWaterBoiling

bull Like total energy E and enthalpy H entropy is a state function

bull Therefore S = Sfinal Sinitial Solid

Liquid

GasENTROPY

ChemicalThermodynamics

Second Law of Thermodynamics

bull the entropy of the universe increases for spontaneous (irreversible) processes

bull the entropy of the universe does not change for reversible processes

Suniv = Ssystem + Ssurroundings gt 0

Suniv = Ssystem + Ssurroundings = 0

ChemicalThermodynamics

Second Law of Thermodynamics

All spontaneous processes cause the entropy of the universe to increase

ENTROPIC DOOMENTROPIC DOOM

So what is our fate as a result of the second law operating in our Universe

ChemicalThermodynamics

Entropy on the Molecular Scalebull Molecules exhibit several types of motion (Kinetic energies)

Translational Movement of a molecule from one place to another Vibrational Periodic motion of atoms within a molecule Rotational Rotation of the molecule on about an axis or rotation about

bonds

bull Boltzmann envisioned the motions of a sample of molecules at a particular instant in time This would be akin to taking a snapshot of all the

molecules He referred to this sampling as a microstate (W) of the

thermodynamic systembull Entropy is helliphellip

S = k ln Whellipwhere k is the Boltzmann constant 138 1023 JK

ChemicalThermodynamics

Entropy on the Molecular Scale

bull The number of microstates (W) and therefore the entropy (S) tends to increase with increases in which variableshellip

Temperature (T)

Volume (V)

The number of independently moving molecules ()

S = k ln Whellipwhere k is the Boltzmann constant 138 1023 JK

ChemicalThermodynamics

Entropy Changes

CaCl2 (s) Ca 2+(aq) + 2Cl-(aq)

H2O

H2O (l) H2O(g)Heat

2 H2O (l) 2 H2 (g) + O2(g)Electricity

16 CO2(g) + 18 H2O(g)2 C8H18 (l) + 25 O2 (g)

gas= 34-25 = +92 = 45 C8H18

bull In which of the following does Entropy increase amp WHYhelliphellipGases are formed from liquids and solids

Liquids or solutions are formed from solids

The number of gas molecules (or moles) increasesEntropySolutionsKMnO4(aq)

EntropyampPhaseOfMatter

bull Entropy increases with the freedom of motion of molecules

S(g) gt S(l) gt S(s)

ChemicalThermodynamics

Third Law of Thermodynamics

The entropy (S) of a pure crystalline substance at absolute zero (-273degC) is 0

ChemicalThermodynamics

Standard Entropiesbull Standard entropies tend to increase with increasing

molar mass

bull Larger and more complex molecules have greater entropies (greater ways to execute molecular motions)

EntropyampMolecuarSize EntropyampTempC7H15 500 K S=921JnK vs 200 K

ChemicalThermodynamics

Absolute Entropy (S)

- 237degC (0 K) S = 0

Standard Entropy (S˚)

25degC (298 K) S =

dT298

0 TC

T

TCS

K 298T

0T

TTC

TTmc

T

q S

Calculate the sum of all the infinitesimally small changes in entropy as T varies from T=0 T= 298 by taking its Integral

Standard Entropies (298 K) from Absolute Entropies (0K)

Sdeg

Temp (K)

Solid Liquid Gas

Hdegfus

Hdegvap

q = mcT

q = mcT

q = mcT

298

S

ChemicalThermodynamics

Entropy Changes in the System

where n and m are the coefficients in the balanced chemical equation

oreactants

oproducts

o298 SmSnS

Sdegsyst = Sdegrxn T

Entropy changes for a reaction (= system) can be estimated in a manner analogous to that by which H is estimated

ChemicalThermodynamics

Problem Calculate the standard entropy changes for the following reaction at 25oC

N2 (g) + 3 H2 (g) 2 NH3 (g)

Sdeg = nSdeg(prod) - mSdeg(react)

Sdeg = - 1983 J

2(1925) ndash [(1915)+3(1306)]

Entropy Changes in the System

ChemicalThermodynamics

oreactants

oproducts

o298 S S S

Thermodynamic Changes in Systems (Chem Reactions)

Appendix 1 (CHM 1046 Module) notice Sdeg is in J not kJ

Grxn = Gf (products) Gf (reactants)

Hrxn = Hf (products) - Hf (reactants)

ChemicalThermodynamics

Entropy Changes in the Surroundings

bull Heat (q) that flows into or out of the system changes the entropy of the surroundings

Ssurr prop - (qsys)bull For an isothermal process

Ssurr= (qsys)T

bull At constant pressure qsys is simply H for the system

System

q

q

qq

q

q

q

Ssurr= Hsys

TSurroundings

What in a chemical reaction causes entropy changes in the surroundings

ChemicalThermodynamics

Entropy Change in the Universe

K 298

1000 692( kJ) Jxmol kJ

Problem Calculate the Suniv for the synthesis of ammonia 25oC

N2 (g) + 3 H2 (g) 2 NH3 (g) Hdegrxn = - 926 kJmol

Ssurr =-Hsys

T

Ssurr = 311 JKmol

Suniv = Ssyst or rxn + Ssurr

nS(prod) - mS(react)

Sdegsyst = - 199 JKmiddotmol

2(1925) ndash [(1915)+3(1306)]

Suniv = - 1983 JKmiddotmol + 311 JKmol

Suniv = 113 JKmol

ChemicalThermodynamics

Entropy Change in the Universe

bull ThenSuniv = Ssyst + Hsystem

T

Suniv = Ssyst or rxn + Ssurr

Ssurr =-Hsys

Tbull Since

TSuniv = Hsyst TSsyst

TSuniv is defined as the Gibbs (free) Energy G

TSuniv = TSsyst + Hsyst

J Willard Gibbs USA 1839-1903

Multiplying both sides by T

ChemicalThermodynamics

bull When Suniv is positive G is negative

bull When G is negative the process is spontaneous

Gibbs Free Energy (G)

Gibbs Energy (-TΔS) measures the useful or process-initiating work obtainable from an isothermal isobaric thermodynamic system Technically the Gibbs free energy is the maximum amount of non-expansion work which can be extracted from a closed system or this maximum can be attained only in a completely reversible process

Guniv = Hsys TSsysTSuniv =

ChemicalThermodynamics

Free Energy Changes

At temperatures other than 25degC

Gdeg = H TS

How does G change with temperature

bull There are two parts to the free energy equation Hmdash the enthalpy term TS mdash the entropy term

bull The temperature dependence of free energy then comes from the entropy term

ChemicalThermodynamics

Spontaneity Enthalpy amp Entropy

Gdeg = H TS

Spontaneous all T

NonSpontaneous all T

Spontaneous high TSpontaneous low T

ChemicalThermodynamics

Spontaneity Enthalpy amp Entropy

Entropy Driven Reactions

Entropy amp Enthalpy Driven Reaction

Enthalpy Driven Reaction

Na2CO3(s) + HCl(aq) NaCl(aq) + CO2 (g)

2 H2(g) + O2 (g) 2 H2O(g)

NH4NO3(s) NH4+

(aq) + NO3-(aq)

n = 2-3 = -1

S = +H = +

G = H( TS)

EntropySyst+SurrFormationOfWater

(-TS)

(-TS)

(+TS)H = - S = -

H = - S = +

Enthalpy EntropyH2O

ChemicalThermodynamics

ProblemsGdeg = HT(S)

(-763)

ndash (-804)

+41

(3549)

ndash (2219)

+1330

Gdeg = H TS = (1313kJ) T(133kJ)

T = 987

TiCl4(l) TiCl4(g)

(-T)Reactant

Product

ChemicalThermodynamics

Standard Free Energy Changes

Analogous to standard enthalpies of formation are standard free energies of formation G

f

G = nG(products) mGf (reactants)f

where n and m are the stoichiometric coefficients

ChemicalThermodynamics

Standard Free Energy Changes

12 CO2(g) + 6 H2O(g)2 C6H6 (l) + 15 O2 (g)

Grxn = nG(prod) mG(react)f

Calculate the standard free energy changes for the above reaction 25 degC

f

[12(-394) + 6(-229)] ndash [2(125) + 15 (0)]

ndash [2 C6H6 (l) + 15 O2(g)][12 CO2(g) + 6 H2O(g)]

Grxn = - 6352 Jmol K

Standard Molar Gibbs Energy of Formation (Gdegf)

CO2 (g) -394

H2O (g) -229

C6H6 (l) 125

ChemicalThermodynamics

Fourth Law of Thermodynamics EmergenceComplex emergent systems spontaneously (-G) arise when energy flows through a collection of many interacting particles resulting in new patterns of complex behaviors that are much more than the sum of the individual parts (+S)

The formation of these complex patterns in emergent systems is more efficient in the dissipation of energy (-H) thus speeds up the increase of entropy in the universe

G = H -TSA precise definition of emergence and a useful mathematical formulation of this phenomenon remains elusive

C f [n i E(t)]Examples cells forming living organisms stars forming galaxies neurons forming conscious brain

ChemicalThermodynamics

ChemicalThermodynamics

ChemicalThermodynamics

ChemicalThermodynamics

ChemicalThermodynamics

ChemicalThermodynamics

ChemicalThermodynamics

2002 B

ChemicalThermodynamics

ChemicalThermodynamics

ChemicalThermodynamics

2003 A

ChemicalThermodynamics

ChemicalThermodynamics

2004 A

ChemicalThermodynamics

ChemicalThermodynamics

ChemicalThermodynamics

2004 B

ChemicalThermodynamics

ChemicalThermodynamics

2005 A

ChemicalThermodynamics

ChemicalThermodynamics

2006 (B)

ChemicalThermodynamics

ChemicalThermodynamics

ChemicalThermodynamics

2007 (A)

ChemicalThermodynamics

ChemicalThermodynamics

  • Unit 14 Chemical Thermodynamics
  • First Law of Thermodynamics
  • Second Law of Thermodynamics
  • Spontaneous Processes
  • Slide 5
  • Spontaneity
  • Irreversible Processes
  • Entropy (S)
  • Slide 9
  • Second Law of Thermodynamics
  • Slide 11
  • Entropy on the Molecular Scale
  • Slide 13
  • Entropy Changes
  • Third Law of Thermodynamics
  • Standard Entropies
  • Standard Entropies (298 K) from Absolute Entropies (0K)
  • Entropy Changes in the System
  • Slide 19
  • Thermodynamic Changes in Systems (Chem Reactions)
  • Entropy Changes in the Surroundings
  • Entropy Change in the Universe
  • Slide 23
  • Gibbs Free Energy (G)
  • Free Energy Changes
  • Spontaneity Enthalpy amp Entropy
  • Slide 27
  • Problems
  • Standard Free Energy Changes
  • Slide 30
  • Fourth Law of Thermodynamics Emergence
  • Slide 32
  • Slide 33
  • Slide 34
  • Slide 35
  • Slide 36
  • Slide 37
  • Slide 38
  • Slide 39
  • Slide 40
  • Slide 41
  • Slide 42
  • Slide 43
  • Slide 44
  • Slide 45
  • Slide 46
  • Slide 47
  • Slide 48
  • Slide 49
  • 2006 (B)
  • Slide 51
  • Slide 52
  • Slide 53
  • Slide 54
  • Slide 55
Page 5: Unit 14: Chemical Thermodynamics

ChemicalThermodynamics

Spontaneous Processesbull Processes that are spontaneous at one temperature

may be nonspontaneous at other temperaturesbull Above 0C it is spontaneous for ice to meltbull Below 0C the reverse process is spontaneous

Is the spontaneity of

melting ice dependent on

anything

Spontaneous T gt 0ordmC

Spontaneous T lt 0ordmC

ChemicalThermodynamics

Spontaneity

Thermodynamics vs Kinetics

C diamond C graphite

vs Speed

ChemicalThermodynamics

Stone

+ Work

Irreversible Processes

bull Heat energy is lost to dissipation and that energy will not be recoverable if the process is reversed

bull Irreversible processes cannot be undone by exactly reversing the change to the system

bull Spontaneous processes are irreversible

In a reversible process the system changes in such a way that the system and surroundings can be put back in their original states by exactly reversing the process

E1

E2

- (work + heat)

Reversible Processes

ChemicalThermodynamics

Entropy (S)

bull Entropy (S) is a term coined by Rudolph Clausius in the 1850rsquos Clausius chose S in honor of Sadi Carnot (who gave the first successful theoretical account of heat engines now known as the Carnot cycle thereby laying the foundations of the second law of thermodynamics)

bull Clausius was convinced of the significance of the ratio of heat delivered and the temperature at which it is delivered

qTEntropy (S) =

Entropy is a measure of the energy that becomes dissipated and unavailable (friction molecular motion = heat)

ChemicalThermodynamics

Entropy (S)bull Entropy can be thought of

as a measure of the randomness (disorder) of a system

bull It is related to the various modes of motion in molecules

EntropyWaterBoiling

bull Like total energy E and enthalpy H entropy is a state function

bull Therefore S = Sfinal Sinitial Solid

Liquid

GasENTROPY

ChemicalThermodynamics

Second Law of Thermodynamics

bull the entropy of the universe increases for spontaneous (irreversible) processes

bull the entropy of the universe does not change for reversible processes

Suniv = Ssystem + Ssurroundings gt 0

Suniv = Ssystem + Ssurroundings = 0

ChemicalThermodynamics

Second Law of Thermodynamics

All spontaneous processes cause the entropy of the universe to increase

ENTROPIC DOOMENTROPIC DOOM

So what is our fate as a result of the second law operating in our Universe

ChemicalThermodynamics

Entropy on the Molecular Scalebull Molecules exhibit several types of motion (Kinetic energies)

Translational Movement of a molecule from one place to another Vibrational Periodic motion of atoms within a molecule Rotational Rotation of the molecule on about an axis or rotation about

bonds

bull Boltzmann envisioned the motions of a sample of molecules at a particular instant in time This would be akin to taking a snapshot of all the

molecules He referred to this sampling as a microstate (W) of the

thermodynamic systembull Entropy is helliphellip

S = k ln Whellipwhere k is the Boltzmann constant 138 1023 JK

ChemicalThermodynamics

Entropy on the Molecular Scale

bull The number of microstates (W) and therefore the entropy (S) tends to increase with increases in which variableshellip

Temperature (T)

Volume (V)

The number of independently moving molecules ()

S = k ln Whellipwhere k is the Boltzmann constant 138 1023 JK

ChemicalThermodynamics

Entropy Changes

CaCl2 (s) Ca 2+(aq) + 2Cl-(aq)

H2O

H2O (l) H2O(g)Heat

2 H2O (l) 2 H2 (g) + O2(g)Electricity

16 CO2(g) + 18 H2O(g)2 C8H18 (l) + 25 O2 (g)

gas= 34-25 = +92 = 45 C8H18

bull In which of the following does Entropy increase amp WHYhelliphellipGases are formed from liquids and solids

Liquids or solutions are formed from solids

The number of gas molecules (or moles) increasesEntropySolutionsKMnO4(aq)

EntropyampPhaseOfMatter

bull Entropy increases with the freedom of motion of molecules

S(g) gt S(l) gt S(s)

ChemicalThermodynamics

Third Law of Thermodynamics

The entropy (S) of a pure crystalline substance at absolute zero (-273degC) is 0

ChemicalThermodynamics

Standard Entropiesbull Standard entropies tend to increase with increasing

molar mass

bull Larger and more complex molecules have greater entropies (greater ways to execute molecular motions)

EntropyampMolecuarSize EntropyampTempC7H15 500 K S=921JnK vs 200 K

ChemicalThermodynamics

Absolute Entropy (S)

- 237degC (0 K) S = 0

Standard Entropy (S˚)

25degC (298 K) S =

dT298

0 TC

T

TCS

K 298T

0T

TTC

TTmc

T

q S

Calculate the sum of all the infinitesimally small changes in entropy as T varies from T=0 T= 298 by taking its Integral

Standard Entropies (298 K) from Absolute Entropies (0K)

Sdeg

Temp (K)

Solid Liquid Gas

Hdegfus

Hdegvap

q = mcT

q = mcT

q = mcT

298

S

ChemicalThermodynamics

Entropy Changes in the System

where n and m are the coefficients in the balanced chemical equation

oreactants

oproducts

o298 SmSnS

Sdegsyst = Sdegrxn T

Entropy changes for a reaction (= system) can be estimated in a manner analogous to that by which H is estimated

ChemicalThermodynamics

Problem Calculate the standard entropy changes for the following reaction at 25oC

N2 (g) + 3 H2 (g) 2 NH3 (g)

Sdeg = nSdeg(prod) - mSdeg(react)

Sdeg = - 1983 J

2(1925) ndash [(1915)+3(1306)]

Entropy Changes in the System

ChemicalThermodynamics

oreactants

oproducts

o298 S S S

Thermodynamic Changes in Systems (Chem Reactions)

Appendix 1 (CHM 1046 Module) notice Sdeg is in J not kJ

Grxn = Gf (products) Gf (reactants)

Hrxn = Hf (products) - Hf (reactants)

ChemicalThermodynamics

Entropy Changes in the Surroundings

bull Heat (q) that flows into or out of the system changes the entropy of the surroundings

Ssurr prop - (qsys)bull For an isothermal process

Ssurr= (qsys)T

bull At constant pressure qsys is simply H for the system

System

q

q

qq

q

q

q

Ssurr= Hsys

TSurroundings

What in a chemical reaction causes entropy changes in the surroundings

ChemicalThermodynamics

Entropy Change in the Universe

K 298

1000 692( kJ) Jxmol kJ

Problem Calculate the Suniv for the synthesis of ammonia 25oC

N2 (g) + 3 H2 (g) 2 NH3 (g) Hdegrxn = - 926 kJmol

Ssurr =-Hsys

T

Ssurr = 311 JKmol

Suniv = Ssyst or rxn + Ssurr

nS(prod) - mS(react)

Sdegsyst = - 199 JKmiddotmol

2(1925) ndash [(1915)+3(1306)]

Suniv = - 1983 JKmiddotmol + 311 JKmol

Suniv = 113 JKmol

ChemicalThermodynamics

Entropy Change in the Universe

bull ThenSuniv = Ssyst + Hsystem

T

Suniv = Ssyst or rxn + Ssurr

Ssurr =-Hsys

Tbull Since

TSuniv = Hsyst TSsyst

TSuniv is defined as the Gibbs (free) Energy G

TSuniv = TSsyst + Hsyst

J Willard Gibbs USA 1839-1903

Multiplying both sides by T

ChemicalThermodynamics

bull When Suniv is positive G is negative

bull When G is negative the process is spontaneous

Gibbs Free Energy (G)

Gibbs Energy (-TΔS) measures the useful or process-initiating work obtainable from an isothermal isobaric thermodynamic system Technically the Gibbs free energy is the maximum amount of non-expansion work which can be extracted from a closed system or this maximum can be attained only in a completely reversible process

Guniv = Hsys TSsysTSuniv =

ChemicalThermodynamics

Free Energy Changes

At temperatures other than 25degC

Gdeg = H TS

How does G change with temperature

bull There are two parts to the free energy equation Hmdash the enthalpy term TS mdash the entropy term

bull The temperature dependence of free energy then comes from the entropy term

ChemicalThermodynamics

Spontaneity Enthalpy amp Entropy

Gdeg = H TS

Spontaneous all T

NonSpontaneous all T

Spontaneous high TSpontaneous low T

ChemicalThermodynamics

Spontaneity Enthalpy amp Entropy

Entropy Driven Reactions

Entropy amp Enthalpy Driven Reaction

Enthalpy Driven Reaction

Na2CO3(s) + HCl(aq) NaCl(aq) + CO2 (g)

2 H2(g) + O2 (g) 2 H2O(g)

NH4NO3(s) NH4+

(aq) + NO3-(aq)

n = 2-3 = -1

S = +H = +

G = H( TS)

EntropySyst+SurrFormationOfWater

(-TS)

(-TS)

(+TS)H = - S = -

H = - S = +

Enthalpy EntropyH2O

ChemicalThermodynamics

ProblemsGdeg = HT(S)

(-763)

ndash (-804)

+41

(3549)

ndash (2219)

+1330

Gdeg = H TS = (1313kJ) T(133kJ)

T = 987

TiCl4(l) TiCl4(g)

(-T)Reactant

Product

ChemicalThermodynamics

Standard Free Energy Changes

Analogous to standard enthalpies of formation are standard free energies of formation G

f

G = nG(products) mGf (reactants)f

where n and m are the stoichiometric coefficients

ChemicalThermodynamics

Standard Free Energy Changes

12 CO2(g) + 6 H2O(g)2 C6H6 (l) + 15 O2 (g)

Grxn = nG(prod) mG(react)f

Calculate the standard free energy changes for the above reaction 25 degC

f

[12(-394) + 6(-229)] ndash [2(125) + 15 (0)]

ndash [2 C6H6 (l) + 15 O2(g)][12 CO2(g) + 6 H2O(g)]

Grxn = - 6352 Jmol K

Standard Molar Gibbs Energy of Formation (Gdegf)

CO2 (g) -394

H2O (g) -229

C6H6 (l) 125

ChemicalThermodynamics

Fourth Law of Thermodynamics EmergenceComplex emergent systems spontaneously (-G) arise when energy flows through a collection of many interacting particles resulting in new patterns of complex behaviors that are much more than the sum of the individual parts (+S)

The formation of these complex patterns in emergent systems is more efficient in the dissipation of energy (-H) thus speeds up the increase of entropy in the universe

G = H -TSA precise definition of emergence and a useful mathematical formulation of this phenomenon remains elusive

C f [n i E(t)]Examples cells forming living organisms stars forming galaxies neurons forming conscious brain

ChemicalThermodynamics

ChemicalThermodynamics

ChemicalThermodynamics

ChemicalThermodynamics

ChemicalThermodynamics

ChemicalThermodynamics

ChemicalThermodynamics

2002 B

ChemicalThermodynamics

ChemicalThermodynamics

ChemicalThermodynamics

2003 A

ChemicalThermodynamics

ChemicalThermodynamics

2004 A

ChemicalThermodynamics

ChemicalThermodynamics

ChemicalThermodynamics

2004 B

ChemicalThermodynamics

ChemicalThermodynamics

2005 A

ChemicalThermodynamics

ChemicalThermodynamics

2006 (B)

ChemicalThermodynamics

ChemicalThermodynamics

ChemicalThermodynamics

2007 (A)

ChemicalThermodynamics

ChemicalThermodynamics

  • Unit 14 Chemical Thermodynamics
  • First Law of Thermodynamics
  • Second Law of Thermodynamics
  • Spontaneous Processes
  • Slide 5
  • Spontaneity
  • Irreversible Processes
  • Entropy (S)
  • Slide 9
  • Second Law of Thermodynamics
  • Slide 11
  • Entropy on the Molecular Scale
  • Slide 13
  • Entropy Changes
  • Third Law of Thermodynamics
  • Standard Entropies
  • Standard Entropies (298 K) from Absolute Entropies (0K)
  • Entropy Changes in the System
  • Slide 19
  • Thermodynamic Changes in Systems (Chem Reactions)
  • Entropy Changes in the Surroundings
  • Entropy Change in the Universe
  • Slide 23
  • Gibbs Free Energy (G)
  • Free Energy Changes
  • Spontaneity Enthalpy amp Entropy
  • Slide 27
  • Problems
  • Standard Free Energy Changes
  • Slide 30
  • Fourth Law of Thermodynamics Emergence
  • Slide 32
  • Slide 33
  • Slide 34
  • Slide 35
  • Slide 36
  • Slide 37
  • Slide 38
  • Slide 39
  • Slide 40
  • Slide 41
  • Slide 42
  • Slide 43
  • Slide 44
  • Slide 45
  • Slide 46
  • Slide 47
  • Slide 48
  • Slide 49
  • 2006 (B)
  • Slide 51
  • Slide 52
  • Slide 53
  • Slide 54
  • Slide 55
Page 6: Unit 14: Chemical Thermodynamics

ChemicalThermodynamics

Spontaneity

Thermodynamics vs Kinetics

C diamond C graphite

vs Speed

ChemicalThermodynamics

Stone

+ Work

Irreversible Processes

bull Heat energy is lost to dissipation and that energy will not be recoverable if the process is reversed

bull Irreversible processes cannot be undone by exactly reversing the change to the system

bull Spontaneous processes are irreversible

In a reversible process the system changes in such a way that the system and surroundings can be put back in their original states by exactly reversing the process

E1

E2

- (work + heat)

Reversible Processes

ChemicalThermodynamics

Entropy (S)

bull Entropy (S) is a term coined by Rudolph Clausius in the 1850rsquos Clausius chose S in honor of Sadi Carnot (who gave the first successful theoretical account of heat engines now known as the Carnot cycle thereby laying the foundations of the second law of thermodynamics)

bull Clausius was convinced of the significance of the ratio of heat delivered and the temperature at which it is delivered

qTEntropy (S) =

Entropy is a measure of the energy that becomes dissipated and unavailable (friction molecular motion = heat)

ChemicalThermodynamics

Entropy (S)bull Entropy can be thought of

as a measure of the randomness (disorder) of a system

bull It is related to the various modes of motion in molecules

EntropyWaterBoiling

bull Like total energy E and enthalpy H entropy is a state function

bull Therefore S = Sfinal Sinitial Solid

Liquid

GasENTROPY

ChemicalThermodynamics

Second Law of Thermodynamics

bull the entropy of the universe increases for spontaneous (irreversible) processes

bull the entropy of the universe does not change for reversible processes

Suniv = Ssystem + Ssurroundings gt 0

Suniv = Ssystem + Ssurroundings = 0

ChemicalThermodynamics

Second Law of Thermodynamics

All spontaneous processes cause the entropy of the universe to increase

ENTROPIC DOOMENTROPIC DOOM

So what is our fate as a result of the second law operating in our Universe

ChemicalThermodynamics

Entropy on the Molecular Scalebull Molecules exhibit several types of motion (Kinetic energies)

Translational Movement of a molecule from one place to another Vibrational Periodic motion of atoms within a molecule Rotational Rotation of the molecule on about an axis or rotation about

bonds

bull Boltzmann envisioned the motions of a sample of molecules at a particular instant in time This would be akin to taking a snapshot of all the

molecules He referred to this sampling as a microstate (W) of the

thermodynamic systembull Entropy is helliphellip

S = k ln Whellipwhere k is the Boltzmann constant 138 1023 JK

ChemicalThermodynamics

Entropy on the Molecular Scale

bull The number of microstates (W) and therefore the entropy (S) tends to increase with increases in which variableshellip

Temperature (T)

Volume (V)

The number of independently moving molecules ()

S = k ln Whellipwhere k is the Boltzmann constant 138 1023 JK

ChemicalThermodynamics

Entropy Changes

CaCl2 (s) Ca 2+(aq) + 2Cl-(aq)

H2O

H2O (l) H2O(g)Heat

2 H2O (l) 2 H2 (g) + O2(g)Electricity

16 CO2(g) + 18 H2O(g)2 C8H18 (l) + 25 O2 (g)

gas= 34-25 = +92 = 45 C8H18

bull In which of the following does Entropy increase amp WHYhelliphellipGases are formed from liquids and solids

Liquids or solutions are formed from solids

The number of gas molecules (or moles) increasesEntropySolutionsKMnO4(aq)

EntropyampPhaseOfMatter

bull Entropy increases with the freedom of motion of molecules

S(g) gt S(l) gt S(s)

ChemicalThermodynamics

Third Law of Thermodynamics

The entropy (S) of a pure crystalline substance at absolute zero (-273degC) is 0

ChemicalThermodynamics

Standard Entropiesbull Standard entropies tend to increase with increasing

molar mass

bull Larger and more complex molecules have greater entropies (greater ways to execute molecular motions)

EntropyampMolecuarSize EntropyampTempC7H15 500 K S=921JnK vs 200 K

ChemicalThermodynamics

Absolute Entropy (S)

- 237degC (0 K) S = 0

Standard Entropy (S˚)

25degC (298 K) S =

dT298

0 TC

T

TCS

K 298T

0T

TTC

TTmc

T

q S

Calculate the sum of all the infinitesimally small changes in entropy as T varies from T=0 T= 298 by taking its Integral

Standard Entropies (298 K) from Absolute Entropies (0K)

Sdeg

Temp (K)

Solid Liquid Gas

Hdegfus

Hdegvap

q = mcT

q = mcT

q = mcT

298

S

ChemicalThermodynamics

Entropy Changes in the System

where n and m are the coefficients in the balanced chemical equation

oreactants

oproducts

o298 SmSnS

Sdegsyst = Sdegrxn T

Entropy changes for a reaction (= system) can be estimated in a manner analogous to that by which H is estimated

ChemicalThermodynamics

Problem Calculate the standard entropy changes for the following reaction at 25oC

N2 (g) + 3 H2 (g) 2 NH3 (g)

Sdeg = nSdeg(prod) - mSdeg(react)

Sdeg = - 1983 J

2(1925) ndash [(1915)+3(1306)]

Entropy Changes in the System

ChemicalThermodynamics

oreactants

oproducts

o298 S S S

Thermodynamic Changes in Systems (Chem Reactions)

Appendix 1 (CHM 1046 Module) notice Sdeg is in J not kJ

Grxn = Gf (products) Gf (reactants)

Hrxn = Hf (products) - Hf (reactants)

ChemicalThermodynamics

Entropy Changes in the Surroundings

bull Heat (q) that flows into or out of the system changes the entropy of the surroundings

Ssurr prop - (qsys)bull For an isothermal process

Ssurr= (qsys)T

bull At constant pressure qsys is simply H for the system

System

q

q

qq

q

q

q

Ssurr= Hsys

TSurroundings

What in a chemical reaction causes entropy changes in the surroundings

ChemicalThermodynamics

Entropy Change in the Universe

K 298

1000 692( kJ) Jxmol kJ

Problem Calculate the Suniv for the synthesis of ammonia 25oC

N2 (g) + 3 H2 (g) 2 NH3 (g) Hdegrxn = - 926 kJmol

Ssurr =-Hsys

T

Ssurr = 311 JKmol

Suniv = Ssyst or rxn + Ssurr

nS(prod) - mS(react)

Sdegsyst = - 199 JKmiddotmol

2(1925) ndash [(1915)+3(1306)]

Suniv = - 1983 JKmiddotmol + 311 JKmol

Suniv = 113 JKmol

ChemicalThermodynamics

Entropy Change in the Universe

bull ThenSuniv = Ssyst + Hsystem

T

Suniv = Ssyst or rxn + Ssurr

Ssurr =-Hsys

Tbull Since

TSuniv = Hsyst TSsyst

TSuniv is defined as the Gibbs (free) Energy G

TSuniv = TSsyst + Hsyst

J Willard Gibbs USA 1839-1903

Multiplying both sides by T

ChemicalThermodynamics

bull When Suniv is positive G is negative

bull When G is negative the process is spontaneous

Gibbs Free Energy (G)

Gibbs Energy (-TΔS) measures the useful or process-initiating work obtainable from an isothermal isobaric thermodynamic system Technically the Gibbs free energy is the maximum amount of non-expansion work which can be extracted from a closed system or this maximum can be attained only in a completely reversible process

Guniv = Hsys TSsysTSuniv =

ChemicalThermodynamics

Free Energy Changes

At temperatures other than 25degC

Gdeg = H TS

How does G change with temperature

bull There are two parts to the free energy equation Hmdash the enthalpy term TS mdash the entropy term

bull The temperature dependence of free energy then comes from the entropy term

ChemicalThermodynamics

Spontaneity Enthalpy amp Entropy

Gdeg = H TS

Spontaneous all T

NonSpontaneous all T

Spontaneous high TSpontaneous low T

ChemicalThermodynamics

Spontaneity Enthalpy amp Entropy

Entropy Driven Reactions

Entropy amp Enthalpy Driven Reaction

Enthalpy Driven Reaction

Na2CO3(s) + HCl(aq) NaCl(aq) + CO2 (g)

2 H2(g) + O2 (g) 2 H2O(g)

NH4NO3(s) NH4+

(aq) + NO3-(aq)

n = 2-3 = -1

S = +H = +

G = H( TS)

EntropySyst+SurrFormationOfWater

(-TS)

(-TS)

(+TS)H = - S = -

H = - S = +

Enthalpy EntropyH2O

ChemicalThermodynamics

ProblemsGdeg = HT(S)

(-763)

ndash (-804)

+41

(3549)

ndash (2219)

+1330

Gdeg = H TS = (1313kJ) T(133kJ)

T = 987

TiCl4(l) TiCl4(g)

(-T)Reactant

Product

ChemicalThermodynamics

Standard Free Energy Changes

Analogous to standard enthalpies of formation are standard free energies of formation G

f

G = nG(products) mGf (reactants)f

where n and m are the stoichiometric coefficients

ChemicalThermodynamics

Standard Free Energy Changes

12 CO2(g) + 6 H2O(g)2 C6H6 (l) + 15 O2 (g)

Grxn = nG(prod) mG(react)f

Calculate the standard free energy changes for the above reaction 25 degC

f

[12(-394) + 6(-229)] ndash [2(125) + 15 (0)]

ndash [2 C6H6 (l) + 15 O2(g)][12 CO2(g) + 6 H2O(g)]

Grxn = - 6352 Jmol K

Standard Molar Gibbs Energy of Formation (Gdegf)

CO2 (g) -394

H2O (g) -229

C6H6 (l) 125

ChemicalThermodynamics

Fourth Law of Thermodynamics EmergenceComplex emergent systems spontaneously (-G) arise when energy flows through a collection of many interacting particles resulting in new patterns of complex behaviors that are much more than the sum of the individual parts (+S)

The formation of these complex patterns in emergent systems is more efficient in the dissipation of energy (-H) thus speeds up the increase of entropy in the universe

G = H -TSA precise definition of emergence and a useful mathematical formulation of this phenomenon remains elusive

C f [n i E(t)]Examples cells forming living organisms stars forming galaxies neurons forming conscious brain

ChemicalThermodynamics

ChemicalThermodynamics

ChemicalThermodynamics

ChemicalThermodynamics

ChemicalThermodynamics

ChemicalThermodynamics

ChemicalThermodynamics

2002 B

ChemicalThermodynamics

ChemicalThermodynamics

ChemicalThermodynamics

2003 A

ChemicalThermodynamics

ChemicalThermodynamics

2004 A

ChemicalThermodynamics

ChemicalThermodynamics

ChemicalThermodynamics

2004 B

ChemicalThermodynamics

ChemicalThermodynamics

2005 A

ChemicalThermodynamics

ChemicalThermodynamics

2006 (B)

ChemicalThermodynamics

ChemicalThermodynamics

ChemicalThermodynamics

2007 (A)

ChemicalThermodynamics

ChemicalThermodynamics

  • Unit 14 Chemical Thermodynamics
  • First Law of Thermodynamics
  • Second Law of Thermodynamics
  • Spontaneous Processes
  • Slide 5
  • Spontaneity
  • Irreversible Processes
  • Entropy (S)
  • Slide 9
  • Second Law of Thermodynamics
  • Slide 11
  • Entropy on the Molecular Scale
  • Slide 13
  • Entropy Changes
  • Third Law of Thermodynamics
  • Standard Entropies
  • Standard Entropies (298 K) from Absolute Entropies (0K)
  • Entropy Changes in the System
  • Slide 19
  • Thermodynamic Changes in Systems (Chem Reactions)
  • Entropy Changes in the Surroundings
  • Entropy Change in the Universe
  • Slide 23
  • Gibbs Free Energy (G)
  • Free Energy Changes
  • Spontaneity Enthalpy amp Entropy
  • Slide 27
  • Problems
  • Standard Free Energy Changes
  • Slide 30
  • Fourth Law of Thermodynamics Emergence
  • Slide 32
  • Slide 33
  • Slide 34
  • Slide 35
  • Slide 36
  • Slide 37
  • Slide 38
  • Slide 39
  • Slide 40
  • Slide 41
  • Slide 42
  • Slide 43
  • Slide 44
  • Slide 45
  • Slide 46
  • Slide 47
  • Slide 48
  • Slide 49
  • 2006 (B)
  • Slide 51
  • Slide 52
  • Slide 53
  • Slide 54
  • Slide 55
Page 7: Unit 14: Chemical Thermodynamics

ChemicalThermodynamics

Stone

+ Work

Irreversible Processes

bull Heat energy is lost to dissipation and that energy will not be recoverable if the process is reversed

bull Irreversible processes cannot be undone by exactly reversing the change to the system

bull Spontaneous processes are irreversible

In a reversible process the system changes in such a way that the system and surroundings can be put back in their original states by exactly reversing the process

E1

E2

- (work + heat)

Reversible Processes

ChemicalThermodynamics

Entropy (S)

bull Entropy (S) is a term coined by Rudolph Clausius in the 1850rsquos Clausius chose S in honor of Sadi Carnot (who gave the first successful theoretical account of heat engines now known as the Carnot cycle thereby laying the foundations of the second law of thermodynamics)

bull Clausius was convinced of the significance of the ratio of heat delivered and the temperature at which it is delivered

qTEntropy (S) =

Entropy is a measure of the energy that becomes dissipated and unavailable (friction molecular motion = heat)

ChemicalThermodynamics

Entropy (S)bull Entropy can be thought of

as a measure of the randomness (disorder) of a system

bull It is related to the various modes of motion in molecules

EntropyWaterBoiling

bull Like total energy E and enthalpy H entropy is a state function

bull Therefore S = Sfinal Sinitial Solid

Liquid

GasENTROPY

ChemicalThermodynamics

Second Law of Thermodynamics

bull the entropy of the universe increases for spontaneous (irreversible) processes

bull the entropy of the universe does not change for reversible processes

Suniv = Ssystem + Ssurroundings gt 0

Suniv = Ssystem + Ssurroundings = 0

ChemicalThermodynamics

Second Law of Thermodynamics

All spontaneous processes cause the entropy of the universe to increase

ENTROPIC DOOMENTROPIC DOOM

So what is our fate as a result of the second law operating in our Universe

ChemicalThermodynamics

Entropy on the Molecular Scalebull Molecules exhibit several types of motion (Kinetic energies)

Translational Movement of a molecule from one place to another Vibrational Periodic motion of atoms within a molecule Rotational Rotation of the molecule on about an axis or rotation about

bonds

bull Boltzmann envisioned the motions of a sample of molecules at a particular instant in time This would be akin to taking a snapshot of all the

molecules He referred to this sampling as a microstate (W) of the

thermodynamic systembull Entropy is helliphellip

S = k ln Whellipwhere k is the Boltzmann constant 138 1023 JK

ChemicalThermodynamics

Entropy on the Molecular Scale

bull The number of microstates (W) and therefore the entropy (S) tends to increase with increases in which variableshellip

Temperature (T)

Volume (V)

The number of independently moving molecules ()

S = k ln Whellipwhere k is the Boltzmann constant 138 1023 JK

ChemicalThermodynamics

Entropy Changes

CaCl2 (s) Ca 2+(aq) + 2Cl-(aq)

H2O

H2O (l) H2O(g)Heat

2 H2O (l) 2 H2 (g) + O2(g)Electricity

16 CO2(g) + 18 H2O(g)2 C8H18 (l) + 25 O2 (g)

gas= 34-25 = +92 = 45 C8H18

bull In which of the following does Entropy increase amp WHYhelliphellipGases are formed from liquids and solids

Liquids or solutions are formed from solids

The number of gas molecules (or moles) increasesEntropySolutionsKMnO4(aq)

EntropyampPhaseOfMatter

bull Entropy increases with the freedom of motion of molecules

S(g) gt S(l) gt S(s)

ChemicalThermodynamics

Third Law of Thermodynamics

The entropy (S) of a pure crystalline substance at absolute zero (-273degC) is 0

ChemicalThermodynamics

Standard Entropiesbull Standard entropies tend to increase with increasing

molar mass

bull Larger and more complex molecules have greater entropies (greater ways to execute molecular motions)

EntropyampMolecuarSize EntropyampTempC7H15 500 K S=921JnK vs 200 K

ChemicalThermodynamics

Absolute Entropy (S)

- 237degC (0 K) S = 0

Standard Entropy (S˚)

25degC (298 K) S =

dT298

0 TC

T

TCS

K 298T

0T

TTC

TTmc

T

q S

Calculate the sum of all the infinitesimally small changes in entropy as T varies from T=0 T= 298 by taking its Integral

Standard Entropies (298 K) from Absolute Entropies (0K)

Sdeg

Temp (K)

Solid Liquid Gas

Hdegfus

Hdegvap

q = mcT

q = mcT

q = mcT

298

S

ChemicalThermodynamics

Entropy Changes in the System

where n and m are the coefficients in the balanced chemical equation

oreactants

oproducts

o298 SmSnS

Sdegsyst = Sdegrxn T

Entropy changes for a reaction (= system) can be estimated in a manner analogous to that by which H is estimated

ChemicalThermodynamics

Problem Calculate the standard entropy changes for the following reaction at 25oC

N2 (g) + 3 H2 (g) 2 NH3 (g)

Sdeg = nSdeg(prod) - mSdeg(react)

Sdeg = - 1983 J

2(1925) ndash [(1915)+3(1306)]

Entropy Changes in the System

ChemicalThermodynamics

oreactants

oproducts

o298 S S S

Thermodynamic Changes in Systems (Chem Reactions)

Appendix 1 (CHM 1046 Module) notice Sdeg is in J not kJ

Grxn = Gf (products) Gf (reactants)

Hrxn = Hf (products) - Hf (reactants)

ChemicalThermodynamics

Entropy Changes in the Surroundings

bull Heat (q) that flows into or out of the system changes the entropy of the surroundings

Ssurr prop - (qsys)bull For an isothermal process

Ssurr= (qsys)T

bull At constant pressure qsys is simply H for the system

System

q

q

qq

q

q

q

Ssurr= Hsys

TSurroundings

What in a chemical reaction causes entropy changes in the surroundings

ChemicalThermodynamics

Entropy Change in the Universe

K 298

1000 692( kJ) Jxmol kJ

Problem Calculate the Suniv for the synthesis of ammonia 25oC

N2 (g) + 3 H2 (g) 2 NH3 (g) Hdegrxn = - 926 kJmol

Ssurr =-Hsys

T

Ssurr = 311 JKmol

Suniv = Ssyst or rxn + Ssurr

nS(prod) - mS(react)

Sdegsyst = - 199 JKmiddotmol

2(1925) ndash [(1915)+3(1306)]

Suniv = - 1983 JKmiddotmol + 311 JKmol

Suniv = 113 JKmol

ChemicalThermodynamics

Entropy Change in the Universe

bull ThenSuniv = Ssyst + Hsystem

T

Suniv = Ssyst or rxn + Ssurr

Ssurr =-Hsys

Tbull Since

TSuniv = Hsyst TSsyst

TSuniv is defined as the Gibbs (free) Energy G

TSuniv = TSsyst + Hsyst

J Willard Gibbs USA 1839-1903

Multiplying both sides by T

ChemicalThermodynamics

bull When Suniv is positive G is negative

bull When G is negative the process is spontaneous

Gibbs Free Energy (G)

Gibbs Energy (-TΔS) measures the useful or process-initiating work obtainable from an isothermal isobaric thermodynamic system Technically the Gibbs free energy is the maximum amount of non-expansion work which can be extracted from a closed system or this maximum can be attained only in a completely reversible process

Guniv = Hsys TSsysTSuniv =

ChemicalThermodynamics

Free Energy Changes

At temperatures other than 25degC

Gdeg = H TS

How does G change with temperature

bull There are two parts to the free energy equation Hmdash the enthalpy term TS mdash the entropy term

bull The temperature dependence of free energy then comes from the entropy term

ChemicalThermodynamics

Spontaneity Enthalpy amp Entropy

Gdeg = H TS

Spontaneous all T

NonSpontaneous all T

Spontaneous high TSpontaneous low T

ChemicalThermodynamics

Spontaneity Enthalpy amp Entropy

Entropy Driven Reactions

Entropy amp Enthalpy Driven Reaction

Enthalpy Driven Reaction

Na2CO3(s) + HCl(aq) NaCl(aq) + CO2 (g)

2 H2(g) + O2 (g) 2 H2O(g)

NH4NO3(s) NH4+

(aq) + NO3-(aq)

n = 2-3 = -1

S = +H = +

G = H( TS)

EntropySyst+SurrFormationOfWater

(-TS)

(-TS)

(+TS)H = - S = -

H = - S = +

Enthalpy EntropyH2O

ChemicalThermodynamics

ProblemsGdeg = HT(S)

(-763)

ndash (-804)

+41

(3549)

ndash (2219)

+1330

Gdeg = H TS = (1313kJ) T(133kJ)

T = 987

TiCl4(l) TiCl4(g)

(-T)Reactant

Product

ChemicalThermodynamics

Standard Free Energy Changes

Analogous to standard enthalpies of formation are standard free energies of formation G

f

G = nG(products) mGf (reactants)f

where n and m are the stoichiometric coefficients

ChemicalThermodynamics

Standard Free Energy Changes

12 CO2(g) + 6 H2O(g)2 C6H6 (l) + 15 O2 (g)

Grxn = nG(prod) mG(react)f

Calculate the standard free energy changes for the above reaction 25 degC

f

[12(-394) + 6(-229)] ndash [2(125) + 15 (0)]

ndash [2 C6H6 (l) + 15 O2(g)][12 CO2(g) + 6 H2O(g)]

Grxn = - 6352 Jmol K

Standard Molar Gibbs Energy of Formation (Gdegf)

CO2 (g) -394

H2O (g) -229

C6H6 (l) 125

ChemicalThermodynamics

Fourth Law of Thermodynamics EmergenceComplex emergent systems spontaneously (-G) arise when energy flows through a collection of many interacting particles resulting in new patterns of complex behaviors that are much more than the sum of the individual parts (+S)

The formation of these complex patterns in emergent systems is more efficient in the dissipation of energy (-H) thus speeds up the increase of entropy in the universe

G = H -TSA precise definition of emergence and a useful mathematical formulation of this phenomenon remains elusive

C f [n i E(t)]Examples cells forming living organisms stars forming galaxies neurons forming conscious brain

ChemicalThermodynamics

ChemicalThermodynamics

ChemicalThermodynamics

ChemicalThermodynamics

ChemicalThermodynamics

ChemicalThermodynamics

ChemicalThermodynamics

2002 B

ChemicalThermodynamics

ChemicalThermodynamics

ChemicalThermodynamics

2003 A

ChemicalThermodynamics

ChemicalThermodynamics

2004 A

ChemicalThermodynamics

ChemicalThermodynamics

ChemicalThermodynamics

2004 B

ChemicalThermodynamics

ChemicalThermodynamics

2005 A

ChemicalThermodynamics

ChemicalThermodynamics

2006 (B)

ChemicalThermodynamics

ChemicalThermodynamics

ChemicalThermodynamics

2007 (A)

ChemicalThermodynamics

ChemicalThermodynamics

  • Unit 14 Chemical Thermodynamics
  • First Law of Thermodynamics
  • Second Law of Thermodynamics
  • Spontaneous Processes
  • Slide 5
  • Spontaneity
  • Irreversible Processes
  • Entropy (S)
  • Slide 9
  • Second Law of Thermodynamics
  • Slide 11
  • Entropy on the Molecular Scale
  • Slide 13
  • Entropy Changes
  • Third Law of Thermodynamics
  • Standard Entropies
  • Standard Entropies (298 K) from Absolute Entropies (0K)
  • Entropy Changes in the System
  • Slide 19
  • Thermodynamic Changes in Systems (Chem Reactions)
  • Entropy Changes in the Surroundings
  • Entropy Change in the Universe
  • Slide 23
  • Gibbs Free Energy (G)
  • Free Energy Changes
  • Spontaneity Enthalpy amp Entropy
  • Slide 27
  • Problems
  • Standard Free Energy Changes
  • Slide 30
  • Fourth Law of Thermodynamics Emergence
  • Slide 32
  • Slide 33
  • Slide 34
  • Slide 35
  • Slide 36
  • Slide 37
  • Slide 38
  • Slide 39
  • Slide 40
  • Slide 41
  • Slide 42
  • Slide 43
  • Slide 44
  • Slide 45
  • Slide 46
  • Slide 47
  • Slide 48
  • Slide 49
  • 2006 (B)
  • Slide 51
  • Slide 52
  • Slide 53
  • Slide 54
  • Slide 55
Page 8: Unit 14: Chemical Thermodynamics

ChemicalThermodynamics

Entropy (S)

bull Entropy (S) is a term coined by Rudolph Clausius in the 1850rsquos Clausius chose S in honor of Sadi Carnot (who gave the first successful theoretical account of heat engines now known as the Carnot cycle thereby laying the foundations of the second law of thermodynamics)

bull Clausius was convinced of the significance of the ratio of heat delivered and the temperature at which it is delivered

qTEntropy (S) =

Entropy is a measure of the energy that becomes dissipated and unavailable (friction molecular motion = heat)

ChemicalThermodynamics

Entropy (S)bull Entropy can be thought of

as a measure of the randomness (disorder) of a system

bull It is related to the various modes of motion in molecules

EntropyWaterBoiling

bull Like total energy E and enthalpy H entropy is a state function

bull Therefore S = Sfinal Sinitial Solid

Liquid

GasENTROPY

ChemicalThermodynamics

Second Law of Thermodynamics

bull the entropy of the universe increases for spontaneous (irreversible) processes

bull the entropy of the universe does not change for reversible processes

Suniv = Ssystem + Ssurroundings gt 0

Suniv = Ssystem + Ssurroundings = 0

ChemicalThermodynamics

Second Law of Thermodynamics

All spontaneous processes cause the entropy of the universe to increase

ENTROPIC DOOMENTROPIC DOOM

So what is our fate as a result of the second law operating in our Universe

ChemicalThermodynamics

Entropy on the Molecular Scalebull Molecules exhibit several types of motion (Kinetic energies)

Translational Movement of a molecule from one place to another Vibrational Periodic motion of atoms within a molecule Rotational Rotation of the molecule on about an axis or rotation about

bonds

bull Boltzmann envisioned the motions of a sample of molecules at a particular instant in time This would be akin to taking a snapshot of all the

molecules He referred to this sampling as a microstate (W) of the

thermodynamic systembull Entropy is helliphellip

S = k ln Whellipwhere k is the Boltzmann constant 138 1023 JK

ChemicalThermodynamics

Entropy on the Molecular Scale

bull The number of microstates (W) and therefore the entropy (S) tends to increase with increases in which variableshellip

Temperature (T)

Volume (V)

The number of independently moving molecules ()

S = k ln Whellipwhere k is the Boltzmann constant 138 1023 JK

ChemicalThermodynamics

Entropy Changes

CaCl2 (s) Ca 2+(aq) + 2Cl-(aq)

H2O

H2O (l) H2O(g)Heat

2 H2O (l) 2 H2 (g) + O2(g)Electricity

16 CO2(g) + 18 H2O(g)2 C8H18 (l) + 25 O2 (g)

gas= 34-25 = +92 = 45 C8H18

bull In which of the following does Entropy increase amp WHYhelliphellipGases are formed from liquids and solids

Liquids or solutions are formed from solids

The number of gas molecules (or moles) increasesEntropySolutionsKMnO4(aq)

EntropyampPhaseOfMatter

bull Entropy increases with the freedom of motion of molecules

S(g) gt S(l) gt S(s)

ChemicalThermodynamics

Third Law of Thermodynamics

The entropy (S) of a pure crystalline substance at absolute zero (-273degC) is 0

ChemicalThermodynamics

Standard Entropiesbull Standard entropies tend to increase with increasing

molar mass

bull Larger and more complex molecules have greater entropies (greater ways to execute molecular motions)

EntropyampMolecuarSize EntropyampTempC7H15 500 K S=921JnK vs 200 K

ChemicalThermodynamics

Absolute Entropy (S)

- 237degC (0 K) S = 0

Standard Entropy (S˚)

25degC (298 K) S =

dT298

0 TC

T

TCS

K 298T

0T

TTC

TTmc

T

q S

Calculate the sum of all the infinitesimally small changes in entropy as T varies from T=0 T= 298 by taking its Integral

Standard Entropies (298 K) from Absolute Entropies (0K)

Sdeg

Temp (K)

Solid Liquid Gas

Hdegfus

Hdegvap

q = mcT

q = mcT

q = mcT

298

S

ChemicalThermodynamics

Entropy Changes in the System

where n and m are the coefficients in the balanced chemical equation

oreactants

oproducts

o298 SmSnS

Sdegsyst = Sdegrxn T

Entropy changes for a reaction (= system) can be estimated in a manner analogous to that by which H is estimated

ChemicalThermodynamics

Problem Calculate the standard entropy changes for the following reaction at 25oC

N2 (g) + 3 H2 (g) 2 NH3 (g)

Sdeg = nSdeg(prod) - mSdeg(react)

Sdeg = - 1983 J

2(1925) ndash [(1915)+3(1306)]

Entropy Changes in the System

ChemicalThermodynamics

oreactants

oproducts

o298 S S S

Thermodynamic Changes in Systems (Chem Reactions)

Appendix 1 (CHM 1046 Module) notice Sdeg is in J not kJ

Grxn = Gf (products) Gf (reactants)

Hrxn = Hf (products) - Hf (reactants)

ChemicalThermodynamics

Entropy Changes in the Surroundings

bull Heat (q) that flows into or out of the system changes the entropy of the surroundings

Ssurr prop - (qsys)bull For an isothermal process

Ssurr= (qsys)T

bull At constant pressure qsys is simply H for the system

System

q

q

qq

q

q

q

Ssurr= Hsys

TSurroundings

What in a chemical reaction causes entropy changes in the surroundings

ChemicalThermodynamics

Entropy Change in the Universe

K 298

1000 692( kJ) Jxmol kJ

Problem Calculate the Suniv for the synthesis of ammonia 25oC

N2 (g) + 3 H2 (g) 2 NH3 (g) Hdegrxn = - 926 kJmol

Ssurr =-Hsys

T

Ssurr = 311 JKmol

Suniv = Ssyst or rxn + Ssurr

nS(prod) - mS(react)

Sdegsyst = - 199 JKmiddotmol

2(1925) ndash [(1915)+3(1306)]

Suniv = - 1983 JKmiddotmol + 311 JKmol

Suniv = 113 JKmol

ChemicalThermodynamics

Entropy Change in the Universe

bull ThenSuniv = Ssyst + Hsystem

T

Suniv = Ssyst or rxn + Ssurr

Ssurr =-Hsys

Tbull Since

TSuniv = Hsyst TSsyst

TSuniv is defined as the Gibbs (free) Energy G

TSuniv = TSsyst + Hsyst

J Willard Gibbs USA 1839-1903

Multiplying both sides by T

ChemicalThermodynamics

bull When Suniv is positive G is negative

bull When G is negative the process is spontaneous

Gibbs Free Energy (G)

Gibbs Energy (-TΔS) measures the useful or process-initiating work obtainable from an isothermal isobaric thermodynamic system Technically the Gibbs free energy is the maximum amount of non-expansion work which can be extracted from a closed system or this maximum can be attained only in a completely reversible process

Guniv = Hsys TSsysTSuniv =

ChemicalThermodynamics

Free Energy Changes

At temperatures other than 25degC

Gdeg = H TS

How does G change with temperature

bull There are two parts to the free energy equation Hmdash the enthalpy term TS mdash the entropy term

bull The temperature dependence of free energy then comes from the entropy term

ChemicalThermodynamics

Spontaneity Enthalpy amp Entropy

Gdeg = H TS

Spontaneous all T

NonSpontaneous all T

Spontaneous high TSpontaneous low T

ChemicalThermodynamics

Spontaneity Enthalpy amp Entropy

Entropy Driven Reactions

Entropy amp Enthalpy Driven Reaction

Enthalpy Driven Reaction

Na2CO3(s) + HCl(aq) NaCl(aq) + CO2 (g)

2 H2(g) + O2 (g) 2 H2O(g)

NH4NO3(s) NH4+

(aq) + NO3-(aq)

n = 2-3 = -1

S = +H = +

G = H( TS)

EntropySyst+SurrFormationOfWater

(-TS)

(-TS)

(+TS)H = - S = -

H = - S = +

Enthalpy EntropyH2O

ChemicalThermodynamics

ProblemsGdeg = HT(S)

(-763)

ndash (-804)

+41

(3549)

ndash (2219)

+1330

Gdeg = H TS = (1313kJ) T(133kJ)

T = 987

TiCl4(l) TiCl4(g)

(-T)Reactant

Product

ChemicalThermodynamics

Standard Free Energy Changes

Analogous to standard enthalpies of formation are standard free energies of formation G

f

G = nG(products) mGf (reactants)f

where n and m are the stoichiometric coefficients

ChemicalThermodynamics

Standard Free Energy Changes

12 CO2(g) + 6 H2O(g)2 C6H6 (l) + 15 O2 (g)

Grxn = nG(prod) mG(react)f

Calculate the standard free energy changes for the above reaction 25 degC

f

[12(-394) + 6(-229)] ndash [2(125) + 15 (0)]

ndash [2 C6H6 (l) + 15 O2(g)][12 CO2(g) + 6 H2O(g)]

Grxn = - 6352 Jmol K

Standard Molar Gibbs Energy of Formation (Gdegf)

CO2 (g) -394

H2O (g) -229

C6H6 (l) 125

ChemicalThermodynamics

Fourth Law of Thermodynamics EmergenceComplex emergent systems spontaneously (-G) arise when energy flows through a collection of many interacting particles resulting in new patterns of complex behaviors that are much more than the sum of the individual parts (+S)

The formation of these complex patterns in emergent systems is more efficient in the dissipation of energy (-H) thus speeds up the increase of entropy in the universe

G = H -TSA precise definition of emergence and a useful mathematical formulation of this phenomenon remains elusive

C f [n i E(t)]Examples cells forming living organisms stars forming galaxies neurons forming conscious brain

ChemicalThermodynamics

ChemicalThermodynamics

ChemicalThermodynamics

ChemicalThermodynamics

ChemicalThermodynamics

ChemicalThermodynamics

ChemicalThermodynamics

2002 B

ChemicalThermodynamics

ChemicalThermodynamics

ChemicalThermodynamics

2003 A

ChemicalThermodynamics

ChemicalThermodynamics

2004 A

ChemicalThermodynamics

ChemicalThermodynamics

ChemicalThermodynamics

2004 B

ChemicalThermodynamics

ChemicalThermodynamics

2005 A

ChemicalThermodynamics

ChemicalThermodynamics

2006 (B)

ChemicalThermodynamics

ChemicalThermodynamics

ChemicalThermodynamics

2007 (A)

ChemicalThermodynamics

ChemicalThermodynamics

  • Unit 14 Chemical Thermodynamics
  • First Law of Thermodynamics
  • Second Law of Thermodynamics
  • Spontaneous Processes
  • Slide 5
  • Spontaneity
  • Irreversible Processes
  • Entropy (S)
  • Slide 9
  • Second Law of Thermodynamics
  • Slide 11
  • Entropy on the Molecular Scale
  • Slide 13
  • Entropy Changes
  • Third Law of Thermodynamics
  • Standard Entropies
  • Standard Entropies (298 K) from Absolute Entropies (0K)
  • Entropy Changes in the System
  • Slide 19
  • Thermodynamic Changes in Systems (Chem Reactions)
  • Entropy Changes in the Surroundings
  • Entropy Change in the Universe
  • Slide 23
  • Gibbs Free Energy (G)
  • Free Energy Changes
  • Spontaneity Enthalpy amp Entropy
  • Slide 27
  • Problems
  • Standard Free Energy Changes
  • Slide 30
  • Fourth Law of Thermodynamics Emergence
  • Slide 32
  • Slide 33
  • Slide 34
  • Slide 35
  • Slide 36
  • Slide 37
  • Slide 38
  • Slide 39
  • Slide 40
  • Slide 41
  • Slide 42
  • Slide 43
  • Slide 44
  • Slide 45
  • Slide 46
  • Slide 47
  • Slide 48
  • Slide 49
  • 2006 (B)
  • Slide 51
  • Slide 52
  • Slide 53
  • Slide 54
  • Slide 55
Page 9: Unit 14: Chemical Thermodynamics

ChemicalThermodynamics

Entropy (S)bull Entropy can be thought of

as a measure of the randomness (disorder) of a system

bull It is related to the various modes of motion in molecules

EntropyWaterBoiling

bull Like total energy E and enthalpy H entropy is a state function

bull Therefore S = Sfinal Sinitial Solid

Liquid

GasENTROPY

ChemicalThermodynamics

Second Law of Thermodynamics

bull the entropy of the universe increases for spontaneous (irreversible) processes

bull the entropy of the universe does not change for reversible processes

Suniv = Ssystem + Ssurroundings gt 0

Suniv = Ssystem + Ssurroundings = 0

ChemicalThermodynamics

Second Law of Thermodynamics

All spontaneous processes cause the entropy of the universe to increase

ENTROPIC DOOMENTROPIC DOOM

So what is our fate as a result of the second law operating in our Universe

ChemicalThermodynamics

Entropy on the Molecular Scalebull Molecules exhibit several types of motion (Kinetic energies)

Translational Movement of a molecule from one place to another Vibrational Periodic motion of atoms within a molecule Rotational Rotation of the molecule on about an axis or rotation about

bonds

bull Boltzmann envisioned the motions of a sample of molecules at a particular instant in time This would be akin to taking a snapshot of all the

molecules He referred to this sampling as a microstate (W) of the

thermodynamic systembull Entropy is helliphellip

S = k ln Whellipwhere k is the Boltzmann constant 138 1023 JK

ChemicalThermodynamics

Entropy on the Molecular Scale

bull The number of microstates (W) and therefore the entropy (S) tends to increase with increases in which variableshellip

Temperature (T)

Volume (V)

The number of independently moving molecules ()

S = k ln Whellipwhere k is the Boltzmann constant 138 1023 JK

ChemicalThermodynamics

Entropy Changes

CaCl2 (s) Ca 2+(aq) + 2Cl-(aq)

H2O

H2O (l) H2O(g)Heat

2 H2O (l) 2 H2 (g) + O2(g)Electricity

16 CO2(g) + 18 H2O(g)2 C8H18 (l) + 25 O2 (g)

gas= 34-25 = +92 = 45 C8H18

bull In which of the following does Entropy increase amp WHYhelliphellipGases are formed from liquids and solids

Liquids or solutions are formed from solids

The number of gas molecules (or moles) increasesEntropySolutionsKMnO4(aq)

EntropyampPhaseOfMatter

bull Entropy increases with the freedom of motion of molecules

S(g) gt S(l) gt S(s)

ChemicalThermodynamics

Third Law of Thermodynamics

The entropy (S) of a pure crystalline substance at absolute zero (-273degC) is 0

ChemicalThermodynamics

Standard Entropiesbull Standard entropies tend to increase with increasing

molar mass

bull Larger and more complex molecules have greater entropies (greater ways to execute molecular motions)

EntropyampMolecuarSize EntropyampTempC7H15 500 K S=921JnK vs 200 K

ChemicalThermodynamics

Absolute Entropy (S)

- 237degC (0 K) S = 0

Standard Entropy (S˚)

25degC (298 K) S =

dT298

0 TC

T

TCS

K 298T

0T

TTC

TTmc

T

q S

Calculate the sum of all the infinitesimally small changes in entropy as T varies from T=0 T= 298 by taking its Integral

Standard Entropies (298 K) from Absolute Entropies (0K)

Sdeg

Temp (K)

Solid Liquid Gas

Hdegfus

Hdegvap

q = mcT

q = mcT

q = mcT

298

S

ChemicalThermodynamics

Entropy Changes in the System

where n and m are the coefficients in the balanced chemical equation

oreactants

oproducts

o298 SmSnS

Sdegsyst = Sdegrxn T

Entropy changes for a reaction (= system) can be estimated in a manner analogous to that by which H is estimated

ChemicalThermodynamics

Problem Calculate the standard entropy changes for the following reaction at 25oC

N2 (g) + 3 H2 (g) 2 NH3 (g)

Sdeg = nSdeg(prod) - mSdeg(react)

Sdeg = - 1983 J

2(1925) ndash [(1915)+3(1306)]

Entropy Changes in the System

ChemicalThermodynamics

oreactants

oproducts

o298 S S S

Thermodynamic Changes in Systems (Chem Reactions)

Appendix 1 (CHM 1046 Module) notice Sdeg is in J not kJ

Grxn = Gf (products) Gf (reactants)

Hrxn = Hf (products) - Hf (reactants)

ChemicalThermodynamics

Entropy Changes in the Surroundings

bull Heat (q) that flows into or out of the system changes the entropy of the surroundings

Ssurr prop - (qsys)bull For an isothermal process

Ssurr= (qsys)T

bull At constant pressure qsys is simply H for the system

System

q

q

qq

q

q

q

Ssurr= Hsys

TSurroundings

What in a chemical reaction causes entropy changes in the surroundings

ChemicalThermodynamics

Entropy Change in the Universe

K 298

1000 692( kJ) Jxmol kJ

Problem Calculate the Suniv for the synthesis of ammonia 25oC

N2 (g) + 3 H2 (g) 2 NH3 (g) Hdegrxn = - 926 kJmol

Ssurr =-Hsys

T

Ssurr = 311 JKmol

Suniv = Ssyst or rxn + Ssurr

nS(prod) - mS(react)

Sdegsyst = - 199 JKmiddotmol

2(1925) ndash [(1915)+3(1306)]

Suniv = - 1983 JKmiddotmol + 311 JKmol

Suniv = 113 JKmol

ChemicalThermodynamics

Entropy Change in the Universe

bull ThenSuniv = Ssyst + Hsystem

T

Suniv = Ssyst or rxn + Ssurr

Ssurr =-Hsys

Tbull Since

TSuniv = Hsyst TSsyst

TSuniv is defined as the Gibbs (free) Energy G

TSuniv = TSsyst + Hsyst

J Willard Gibbs USA 1839-1903

Multiplying both sides by T

ChemicalThermodynamics

bull When Suniv is positive G is negative

bull When G is negative the process is spontaneous

Gibbs Free Energy (G)

Gibbs Energy (-TΔS) measures the useful or process-initiating work obtainable from an isothermal isobaric thermodynamic system Technically the Gibbs free energy is the maximum amount of non-expansion work which can be extracted from a closed system or this maximum can be attained only in a completely reversible process

Guniv = Hsys TSsysTSuniv =

ChemicalThermodynamics

Free Energy Changes

At temperatures other than 25degC

Gdeg = H TS

How does G change with temperature

bull There are two parts to the free energy equation Hmdash the enthalpy term TS mdash the entropy term

bull The temperature dependence of free energy then comes from the entropy term

ChemicalThermodynamics

Spontaneity Enthalpy amp Entropy

Gdeg = H TS

Spontaneous all T

NonSpontaneous all T

Spontaneous high TSpontaneous low T

ChemicalThermodynamics

Spontaneity Enthalpy amp Entropy

Entropy Driven Reactions

Entropy amp Enthalpy Driven Reaction

Enthalpy Driven Reaction

Na2CO3(s) + HCl(aq) NaCl(aq) + CO2 (g)

2 H2(g) + O2 (g) 2 H2O(g)

NH4NO3(s) NH4+

(aq) + NO3-(aq)

n = 2-3 = -1

S = +H = +

G = H( TS)

EntropySyst+SurrFormationOfWater

(-TS)

(-TS)

(+TS)H = - S = -

H = - S = +

Enthalpy EntropyH2O

ChemicalThermodynamics

ProblemsGdeg = HT(S)

(-763)

ndash (-804)

+41

(3549)

ndash (2219)

+1330

Gdeg = H TS = (1313kJ) T(133kJ)

T = 987

TiCl4(l) TiCl4(g)

(-T)Reactant

Product

ChemicalThermodynamics

Standard Free Energy Changes

Analogous to standard enthalpies of formation are standard free energies of formation G

f

G = nG(products) mGf (reactants)f

where n and m are the stoichiometric coefficients

ChemicalThermodynamics

Standard Free Energy Changes

12 CO2(g) + 6 H2O(g)2 C6H6 (l) + 15 O2 (g)

Grxn = nG(prod) mG(react)f

Calculate the standard free energy changes for the above reaction 25 degC

f

[12(-394) + 6(-229)] ndash [2(125) + 15 (0)]

ndash [2 C6H6 (l) + 15 O2(g)][12 CO2(g) + 6 H2O(g)]

Grxn = - 6352 Jmol K

Standard Molar Gibbs Energy of Formation (Gdegf)

CO2 (g) -394

H2O (g) -229

C6H6 (l) 125

ChemicalThermodynamics

Fourth Law of Thermodynamics EmergenceComplex emergent systems spontaneously (-G) arise when energy flows through a collection of many interacting particles resulting in new patterns of complex behaviors that are much more than the sum of the individual parts (+S)

The formation of these complex patterns in emergent systems is more efficient in the dissipation of energy (-H) thus speeds up the increase of entropy in the universe

G = H -TSA precise definition of emergence and a useful mathematical formulation of this phenomenon remains elusive

C f [n i E(t)]Examples cells forming living organisms stars forming galaxies neurons forming conscious brain

ChemicalThermodynamics

ChemicalThermodynamics

ChemicalThermodynamics

ChemicalThermodynamics

ChemicalThermodynamics

ChemicalThermodynamics

ChemicalThermodynamics

2002 B

ChemicalThermodynamics

ChemicalThermodynamics

ChemicalThermodynamics

2003 A

ChemicalThermodynamics

ChemicalThermodynamics

2004 A

ChemicalThermodynamics

ChemicalThermodynamics

ChemicalThermodynamics

2004 B

ChemicalThermodynamics

ChemicalThermodynamics

2005 A

ChemicalThermodynamics

ChemicalThermodynamics

2006 (B)

ChemicalThermodynamics

ChemicalThermodynamics

ChemicalThermodynamics

2007 (A)

ChemicalThermodynamics

ChemicalThermodynamics

  • Unit 14 Chemical Thermodynamics
  • First Law of Thermodynamics
  • Second Law of Thermodynamics
  • Spontaneous Processes
  • Slide 5
  • Spontaneity
  • Irreversible Processes
  • Entropy (S)
  • Slide 9
  • Second Law of Thermodynamics
  • Slide 11
  • Entropy on the Molecular Scale
  • Slide 13
  • Entropy Changes
  • Third Law of Thermodynamics
  • Standard Entropies
  • Standard Entropies (298 K) from Absolute Entropies (0K)
  • Entropy Changes in the System
  • Slide 19
  • Thermodynamic Changes in Systems (Chem Reactions)
  • Entropy Changes in the Surroundings
  • Entropy Change in the Universe
  • Slide 23
  • Gibbs Free Energy (G)
  • Free Energy Changes
  • Spontaneity Enthalpy amp Entropy
  • Slide 27
  • Problems
  • Standard Free Energy Changes
  • Slide 30
  • Fourth Law of Thermodynamics Emergence
  • Slide 32
  • Slide 33
  • Slide 34
  • Slide 35
  • Slide 36
  • Slide 37
  • Slide 38
  • Slide 39
  • Slide 40
  • Slide 41
  • Slide 42
  • Slide 43
  • Slide 44
  • Slide 45
  • Slide 46
  • Slide 47
  • Slide 48
  • Slide 49
  • 2006 (B)
  • Slide 51
  • Slide 52
  • Slide 53
  • Slide 54
  • Slide 55
Page 10: Unit 14: Chemical Thermodynamics

ChemicalThermodynamics

Second Law of Thermodynamics

bull the entropy of the universe increases for spontaneous (irreversible) processes

bull the entropy of the universe does not change for reversible processes

Suniv = Ssystem + Ssurroundings gt 0

Suniv = Ssystem + Ssurroundings = 0

ChemicalThermodynamics

Second Law of Thermodynamics

All spontaneous processes cause the entropy of the universe to increase

ENTROPIC DOOMENTROPIC DOOM

So what is our fate as a result of the second law operating in our Universe

ChemicalThermodynamics

Entropy on the Molecular Scalebull Molecules exhibit several types of motion (Kinetic energies)

Translational Movement of a molecule from one place to another Vibrational Periodic motion of atoms within a molecule Rotational Rotation of the molecule on about an axis or rotation about

bonds

bull Boltzmann envisioned the motions of a sample of molecules at a particular instant in time This would be akin to taking a snapshot of all the

molecules He referred to this sampling as a microstate (W) of the

thermodynamic systembull Entropy is helliphellip

S = k ln Whellipwhere k is the Boltzmann constant 138 1023 JK

ChemicalThermodynamics

Entropy on the Molecular Scale

bull The number of microstates (W) and therefore the entropy (S) tends to increase with increases in which variableshellip

Temperature (T)

Volume (V)

The number of independently moving molecules ()

S = k ln Whellipwhere k is the Boltzmann constant 138 1023 JK

ChemicalThermodynamics

Entropy Changes

CaCl2 (s) Ca 2+(aq) + 2Cl-(aq)

H2O

H2O (l) H2O(g)Heat

2 H2O (l) 2 H2 (g) + O2(g)Electricity

16 CO2(g) + 18 H2O(g)2 C8H18 (l) + 25 O2 (g)

gas= 34-25 = +92 = 45 C8H18

bull In which of the following does Entropy increase amp WHYhelliphellipGases are formed from liquids and solids

Liquids or solutions are formed from solids

The number of gas molecules (or moles) increasesEntropySolutionsKMnO4(aq)

EntropyampPhaseOfMatter

bull Entropy increases with the freedom of motion of molecules

S(g) gt S(l) gt S(s)

ChemicalThermodynamics

Third Law of Thermodynamics

The entropy (S) of a pure crystalline substance at absolute zero (-273degC) is 0

ChemicalThermodynamics

Standard Entropiesbull Standard entropies tend to increase with increasing

molar mass

bull Larger and more complex molecules have greater entropies (greater ways to execute molecular motions)

EntropyampMolecuarSize EntropyampTempC7H15 500 K S=921JnK vs 200 K

ChemicalThermodynamics

Absolute Entropy (S)

- 237degC (0 K) S = 0

Standard Entropy (S˚)

25degC (298 K) S =

dT298

0 TC

T

TCS

K 298T

0T

TTC

TTmc

T

q S

Calculate the sum of all the infinitesimally small changes in entropy as T varies from T=0 T= 298 by taking its Integral

Standard Entropies (298 K) from Absolute Entropies (0K)

Sdeg

Temp (K)

Solid Liquid Gas

Hdegfus

Hdegvap

q = mcT

q = mcT

q = mcT

298

S

ChemicalThermodynamics

Entropy Changes in the System

where n and m are the coefficients in the balanced chemical equation

oreactants

oproducts

o298 SmSnS

Sdegsyst = Sdegrxn T

Entropy changes for a reaction (= system) can be estimated in a manner analogous to that by which H is estimated

ChemicalThermodynamics

Problem Calculate the standard entropy changes for the following reaction at 25oC

N2 (g) + 3 H2 (g) 2 NH3 (g)

Sdeg = nSdeg(prod) - mSdeg(react)

Sdeg = - 1983 J

2(1925) ndash [(1915)+3(1306)]

Entropy Changes in the System

ChemicalThermodynamics

oreactants

oproducts

o298 S S S

Thermodynamic Changes in Systems (Chem Reactions)

Appendix 1 (CHM 1046 Module) notice Sdeg is in J not kJ

Grxn = Gf (products) Gf (reactants)

Hrxn = Hf (products) - Hf (reactants)

ChemicalThermodynamics

Entropy Changes in the Surroundings

bull Heat (q) that flows into or out of the system changes the entropy of the surroundings

Ssurr prop - (qsys)bull For an isothermal process

Ssurr= (qsys)T

bull At constant pressure qsys is simply H for the system

System

q

q

qq

q

q

q

Ssurr= Hsys

TSurroundings

What in a chemical reaction causes entropy changes in the surroundings

ChemicalThermodynamics

Entropy Change in the Universe

K 298

1000 692( kJ) Jxmol kJ

Problem Calculate the Suniv for the synthesis of ammonia 25oC

N2 (g) + 3 H2 (g) 2 NH3 (g) Hdegrxn = - 926 kJmol

Ssurr =-Hsys

T

Ssurr = 311 JKmol

Suniv = Ssyst or rxn + Ssurr

nS(prod) - mS(react)

Sdegsyst = - 199 JKmiddotmol

2(1925) ndash [(1915)+3(1306)]

Suniv = - 1983 JKmiddotmol + 311 JKmol

Suniv = 113 JKmol

ChemicalThermodynamics

Entropy Change in the Universe

bull ThenSuniv = Ssyst + Hsystem

T

Suniv = Ssyst or rxn + Ssurr

Ssurr =-Hsys

Tbull Since

TSuniv = Hsyst TSsyst

TSuniv is defined as the Gibbs (free) Energy G

TSuniv = TSsyst + Hsyst

J Willard Gibbs USA 1839-1903

Multiplying both sides by T

ChemicalThermodynamics

bull When Suniv is positive G is negative

bull When G is negative the process is spontaneous

Gibbs Free Energy (G)

Gibbs Energy (-TΔS) measures the useful or process-initiating work obtainable from an isothermal isobaric thermodynamic system Technically the Gibbs free energy is the maximum amount of non-expansion work which can be extracted from a closed system or this maximum can be attained only in a completely reversible process

Guniv = Hsys TSsysTSuniv =

ChemicalThermodynamics

Free Energy Changes

At temperatures other than 25degC

Gdeg = H TS

How does G change with temperature

bull There are two parts to the free energy equation Hmdash the enthalpy term TS mdash the entropy term

bull The temperature dependence of free energy then comes from the entropy term

ChemicalThermodynamics

Spontaneity Enthalpy amp Entropy

Gdeg = H TS

Spontaneous all T

NonSpontaneous all T

Spontaneous high TSpontaneous low T

ChemicalThermodynamics

Spontaneity Enthalpy amp Entropy

Entropy Driven Reactions

Entropy amp Enthalpy Driven Reaction

Enthalpy Driven Reaction

Na2CO3(s) + HCl(aq) NaCl(aq) + CO2 (g)

2 H2(g) + O2 (g) 2 H2O(g)

NH4NO3(s) NH4+

(aq) + NO3-(aq)

n = 2-3 = -1

S = +H = +

G = H( TS)

EntropySyst+SurrFormationOfWater

(-TS)

(-TS)

(+TS)H = - S = -

H = - S = +

Enthalpy EntropyH2O

ChemicalThermodynamics

ProblemsGdeg = HT(S)

(-763)

ndash (-804)

+41

(3549)

ndash (2219)

+1330

Gdeg = H TS = (1313kJ) T(133kJ)

T = 987

TiCl4(l) TiCl4(g)

(-T)Reactant

Product

ChemicalThermodynamics

Standard Free Energy Changes

Analogous to standard enthalpies of formation are standard free energies of formation G

f

G = nG(products) mGf (reactants)f

where n and m are the stoichiometric coefficients

ChemicalThermodynamics

Standard Free Energy Changes

12 CO2(g) + 6 H2O(g)2 C6H6 (l) + 15 O2 (g)

Grxn = nG(prod) mG(react)f

Calculate the standard free energy changes for the above reaction 25 degC

f

[12(-394) + 6(-229)] ndash [2(125) + 15 (0)]

ndash [2 C6H6 (l) + 15 O2(g)][12 CO2(g) + 6 H2O(g)]

Grxn = - 6352 Jmol K

Standard Molar Gibbs Energy of Formation (Gdegf)

CO2 (g) -394

H2O (g) -229

C6H6 (l) 125

ChemicalThermodynamics

Fourth Law of Thermodynamics EmergenceComplex emergent systems spontaneously (-G) arise when energy flows through a collection of many interacting particles resulting in new patterns of complex behaviors that are much more than the sum of the individual parts (+S)

The formation of these complex patterns in emergent systems is more efficient in the dissipation of energy (-H) thus speeds up the increase of entropy in the universe

G = H -TSA precise definition of emergence and a useful mathematical formulation of this phenomenon remains elusive

C f [n i E(t)]Examples cells forming living organisms stars forming galaxies neurons forming conscious brain

ChemicalThermodynamics

ChemicalThermodynamics

ChemicalThermodynamics

ChemicalThermodynamics

ChemicalThermodynamics

ChemicalThermodynamics

ChemicalThermodynamics

2002 B

ChemicalThermodynamics

ChemicalThermodynamics

ChemicalThermodynamics

2003 A

ChemicalThermodynamics

ChemicalThermodynamics

2004 A

ChemicalThermodynamics

ChemicalThermodynamics

ChemicalThermodynamics

2004 B

ChemicalThermodynamics

ChemicalThermodynamics

2005 A

ChemicalThermodynamics

ChemicalThermodynamics

2006 (B)

ChemicalThermodynamics

ChemicalThermodynamics

ChemicalThermodynamics

2007 (A)

ChemicalThermodynamics

ChemicalThermodynamics

  • Unit 14 Chemical Thermodynamics
  • First Law of Thermodynamics
  • Second Law of Thermodynamics
  • Spontaneous Processes
  • Slide 5
  • Spontaneity
  • Irreversible Processes
  • Entropy (S)
  • Slide 9
  • Second Law of Thermodynamics
  • Slide 11
  • Entropy on the Molecular Scale
  • Slide 13
  • Entropy Changes
  • Third Law of Thermodynamics
  • Standard Entropies
  • Standard Entropies (298 K) from Absolute Entropies (0K)
  • Entropy Changes in the System
  • Slide 19
  • Thermodynamic Changes in Systems (Chem Reactions)
  • Entropy Changes in the Surroundings
  • Entropy Change in the Universe
  • Slide 23
  • Gibbs Free Energy (G)
  • Free Energy Changes
  • Spontaneity Enthalpy amp Entropy
  • Slide 27
  • Problems
  • Standard Free Energy Changes
  • Slide 30
  • Fourth Law of Thermodynamics Emergence
  • Slide 32
  • Slide 33
  • Slide 34
  • Slide 35
  • Slide 36
  • Slide 37
  • Slide 38
  • Slide 39
  • Slide 40
  • Slide 41
  • Slide 42
  • Slide 43
  • Slide 44
  • Slide 45
  • Slide 46
  • Slide 47
  • Slide 48
  • Slide 49
  • 2006 (B)
  • Slide 51
  • Slide 52
  • Slide 53
  • Slide 54
  • Slide 55
Page 11: Unit 14: Chemical Thermodynamics

ChemicalThermodynamics

Second Law of Thermodynamics

All spontaneous processes cause the entropy of the universe to increase

ENTROPIC DOOMENTROPIC DOOM

So what is our fate as a result of the second law operating in our Universe

ChemicalThermodynamics

Entropy on the Molecular Scalebull Molecules exhibit several types of motion (Kinetic energies)

Translational Movement of a molecule from one place to another Vibrational Periodic motion of atoms within a molecule Rotational Rotation of the molecule on about an axis or rotation about

bonds

bull Boltzmann envisioned the motions of a sample of molecules at a particular instant in time This would be akin to taking a snapshot of all the

molecules He referred to this sampling as a microstate (W) of the

thermodynamic systembull Entropy is helliphellip

S = k ln Whellipwhere k is the Boltzmann constant 138 1023 JK

ChemicalThermodynamics

Entropy on the Molecular Scale

bull The number of microstates (W) and therefore the entropy (S) tends to increase with increases in which variableshellip

Temperature (T)

Volume (V)

The number of independently moving molecules ()

S = k ln Whellipwhere k is the Boltzmann constant 138 1023 JK

ChemicalThermodynamics

Entropy Changes

CaCl2 (s) Ca 2+(aq) + 2Cl-(aq)

H2O

H2O (l) H2O(g)Heat

2 H2O (l) 2 H2 (g) + O2(g)Electricity

16 CO2(g) + 18 H2O(g)2 C8H18 (l) + 25 O2 (g)

gas= 34-25 = +92 = 45 C8H18

bull In which of the following does Entropy increase amp WHYhelliphellipGases are formed from liquids and solids

Liquids or solutions are formed from solids

The number of gas molecules (or moles) increasesEntropySolutionsKMnO4(aq)

EntropyampPhaseOfMatter

bull Entropy increases with the freedom of motion of molecules

S(g) gt S(l) gt S(s)

ChemicalThermodynamics

Third Law of Thermodynamics

The entropy (S) of a pure crystalline substance at absolute zero (-273degC) is 0

ChemicalThermodynamics

Standard Entropiesbull Standard entropies tend to increase with increasing

molar mass

bull Larger and more complex molecules have greater entropies (greater ways to execute molecular motions)

EntropyampMolecuarSize EntropyampTempC7H15 500 K S=921JnK vs 200 K

ChemicalThermodynamics

Absolute Entropy (S)

- 237degC (0 K) S = 0

Standard Entropy (S˚)

25degC (298 K) S =

dT298

0 TC

T

TCS

K 298T

0T

TTC

TTmc

T

q S

Calculate the sum of all the infinitesimally small changes in entropy as T varies from T=0 T= 298 by taking its Integral

Standard Entropies (298 K) from Absolute Entropies (0K)

Sdeg

Temp (K)

Solid Liquid Gas

Hdegfus

Hdegvap

q = mcT

q = mcT

q = mcT

298

S

ChemicalThermodynamics

Entropy Changes in the System

where n and m are the coefficients in the balanced chemical equation

oreactants

oproducts

o298 SmSnS

Sdegsyst = Sdegrxn T

Entropy changes for a reaction (= system) can be estimated in a manner analogous to that by which H is estimated

ChemicalThermodynamics

Problem Calculate the standard entropy changes for the following reaction at 25oC

N2 (g) + 3 H2 (g) 2 NH3 (g)

Sdeg = nSdeg(prod) - mSdeg(react)

Sdeg = - 1983 J

2(1925) ndash [(1915)+3(1306)]

Entropy Changes in the System

ChemicalThermodynamics

oreactants

oproducts

o298 S S S

Thermodynamic Changes in Systems (Chem Reactions)

Appendix 1 (CHM 1046 Module) notice Sdeg is in J not kJ

Grxn = Gf (products) Gf (reactants)

Hrxn = Hf (products) - Hf (reactants)

ChemicalThermodynamics

Entropy Changes in the Surroundings

bull Heat (q) that flows into or out of the system changes the entropy of the surroundings

Ssurr prop - (qsys)bull For an isothermal process

Ssurr= (qsys)T

bull At constant pressure qsys is simply H for the system

System

q

q

qq

q

q

q

Ssurr= Hsys

TSurroundings

What in a chemical reaction causes entropy changes in the surroundings

ChemicalThermodynamics

Entropy Change in the Universe

K 298

1000 692( kJ) Jxmol kJ

Problem Calculate the Suniv for the synthesis of ammonia 25oC

N2 (g) + 3 H2 (g) 2 NH3 (g) Hdegrxn = - 926 kJmol

Ssurr =-Hsys

T

Ssurr = 311 JKmol

Suniv = Ssyst or rxn + Ssurr

nS(prod) - mS(react)

Sdegsyst = - 199 JKmiddotmol

2(1925) ndash [(1915)+3(1306)]

Suniv = - 1983 JKmiddotmol + 311 JKmol

Suniv = 113 JKmol

ChemicalThermodynamics

Entropy Change in the Universe

bull ThenSuniv = Ssyst + Hsystem

T

Suniv = Ssyst or rxn + Ssurr

Ssurr =-Hsys

Tbull Since

TSuniv = Hsyst TSsyst

TSuniv is defined as the Gibbs (free) Energy G

TSuniv = TSsyst + Hsyst

J Willard Gibbs USA 1839-1903

Multiplying both sides by T

ChemicalThermodynamics

bull When Suniv is positive G is negative

bull When G is negative the process is spontaneous

Gibbs Free Energy (G)

Gibbs Energy (-TΔS) measures the useful or process-initiating work obtainable from an isothermal isobaric thermodynamic system Technically the Gibbs free energy is the maximum amount of non-expansion work which can be extracted from a closed system or this maximum can be attained only in a completely reversible process

Guniv = Hsys TSsysTSuniv =

ChemicalThermodynamics

Free Energy Changes

At temperatures other than 25degC

Gdeg = H TS

How does G change with temperature

bull There are two parts to the free energy equation Hmdash the enthalpy term TS mdash the entropy term

bull The temperature dependence of free energy then comes from the entropy term

ChemicalThermodynamics

Spontaneity Enthalpy amp Entropy

Gdeg = H TS

Spontaneous all T

NonSpontaneous all T

Spontaneous high TSpontaneous low T

ChemicalThermodynamics

Spontaneity Enthalpy amp Entropy

Entropy Driven Reactions

Entropy amp Enthalpy Driven Reaction

Enthalpy Driven Reaction

Na2CO3(s) + HCl(aq) NaCl(aq) + CO2 (g)

2 H2(g) + O2 (g) 2 H2O(g)

NH4NO3(s) NH4+

(aq) + NO3-(aq)

n = 2-3 = -1

S = +H = +

G = H( TS)

EntropySyst+SurrFormationOfWater

(-TS)

(-TS)

(+TS)H = - S = -

H = - S = +

Enthalpy EntropyH2O

ChemicalThermodynamics

ProblemsGdeg = HT(S)

(-763)

ndash (-804)

+41

(3549)

ndash (2219)

+1330

Gdeg = H TS = (1313kJ) T(133kJ)

T = 987

TiCl4(l) TiCl4(g)

(-T)Reactant

Product

ChemicalThermodynamics

Standard Free Energy Changes

Analogous to standard enthalpies of formation are standard free energies of formation G

f

G = nG(products) mGf (reactants)f

where n and m are the stoichiometric coefficients

ChemicalThermodynamics

Standard Free Energy Changes

12 CO2(g) + 6 H2O(g)2 C6H6 (l) + 15 O2 (g)

Grxn = nG(prod) mG(react)f

Calculate the standard free energy changes for the above reaction 25 degC

f

[12(-394) + 6(-229)] ndash [2(125) + 15 (0)]

ndash [2 C6H6 (l) + 15 O2(g)][12 CO2(g) + 6 H2O(g)]

Grxn = - 6352 Jmol K

Standard Molar Gibbs Energy of Formation (Gdegf)

CO2 (g) -394

H2O (g) -229

C6H6 (l) 125

ChemicalThermodynamics

Fourth Law of Thermodynamics EmergenceComplex emergent systems spontaneously (-G) arise when energy flows through a collection of many interacting particles resulting in new patterns of complex behaviors that are much more than the sum of the individual parts (+S)

The formation of these complex patterns in emergent systems is more efficient in the dissipation of energy (-H) thus speeds up the increase of entropy in the universe

G = H -TSA precise definition of emergence and a useful mathematical formulation of this phenomenon remains elusive

C f [n i E(t)]Examples cells forming living organisms stars forming galaxies neurons forming conscious brain

ChemicalThermodynamics

ChemicalThermodynamics

ChemicalThermodynamics

ChemicalThermodynamics

ChemicalThermodynamics

ChemicalThermodynamics

ChemicalThermodynamics

2002 B

ChemicalThermodynamics

ChemicalThermodynamics

ChemicalThermodynamics

2003 A

ChemicalThermodynamics

ChemicalThermodynamics

2004 A

ChemicalThermodynamics

ChemicalThermodynamics

ChemicalThermodynamics

2004 B

ChemicalThermodynamics

ChemicalThermodynamics

2005 A

ChemicalThermodynamics

ChemicalThermodynamics

2006 (B)

ChemicalThermodynamics

ChemicalThermodynamics

ChemicalThermodynamics

2007 (A)

ChemicalThermodynamics

ChemicalThermodynamics

  • Unit 14 Chemical Thermodynamics
  • First Law of Thermodynamics
  • Second Law of Thermodynamics
  • Spontaneous Processes
  • Slide 5
  • Spontaneity
  • Irreversible Processes
  • Entropy (S)
  • Slide 9
  • Second Law of Thermodynamics
  • Slide 11
  • Entropy on the Molecular Scale
  • Slide 13
  • Entropy Changes
  • Third Law of Thermodynamics
  • Standard Entropies
  • Standard Entropies (298 K) from Absolute Entropies (0K)
  • Entropy Changes in the System
  • Slide 19
  • Thermodynamic Changes in Systems (Chem Reactions)
  • Entropy Changes in the Surroundings
  • Entropy Change in the Universe
  • Slide 23
  • Gibbs Free Energy (G)
  • Free Energy Changes
  • Spontaneity Enthalpy amp Entropy
  • Slide 27
  • Problems
  • Standard Free Energy Changes
  • Slide 30
  • Fourth Law of Thermodynamics Emergence
  • Slide 32
  • Slide 33
  • Slide 34
  • Slide 35
  • Slide 36
  • Slide 37
  • Slide 38
  • Slide 39
  • Slide 40
  • Slide 41
  • Slide 42
  • Slide 43
  • Slide 44
  • Slide 45
  • Slide 46
  • Slide 47
  • Slide 48
  • Slide 49
  • 2006 (B)
  • Slide 51
  • Slide 52
  • Slide 53
  • Slide 54
  • Slide 55
Page 12: Unit 14: Chemical Thermodynamics

ChemicalThermodynamics

Entropy on the Molecular Scalebull Molecules exhibit several types of motion (Kinetic energies)

Translational Movement of a molecule from one place to another Vibrational Periodic motion of atoms within a molecule Rotational Rotation of the molecule on about an axis or rotation about

bonds

bull Boltzmann envisioned the motions of a sample of molecules at a particular instant in time This would be akin to taking a snapshot of all the

molecules He referred to this sampling as a microstate (W) of the

thermodynamic systembull Entropy is helliphellip

S = k ln Whellipwhere k is the Boltzmann constant 138 1023 JK

ChemicalThermodynamics

Entropy on the Molecular Scale

bull The number of microstates (W) and therefore the entropy (S) tends to increase with increases in which variableshellip

Temperature (T)

Volume (V)

The number of independently moving molecules ()

S = k ln Whellipwhere k is the Boltzmann constant 138 1023 JK

ChemicalThermodynamics

Entropy Changes

CaCl2 (s) Ca 2+(aq) + 2Cl-(aq)

H2O

H2O (l) H2O(g)Heat

2 H2O (l) 2 H2 (g) + O2(g)Electricity

16 CO2(g) + 18 H2O(g)2 C8H18 (l) + 25 O2 (g)

gas= 34-25 = +92 = 45 C8H18

bull In which of the following does Entropy increase amp WHYhelliphellipGases are formed from liquids and solids

Liquids or solutions are formed from solids

The number of gas molecules (or moles) increasesEntropySolutionsKMnO4(aq)

EntropyampPhaseOfMatter

bull Entropy increases with the freedom of motion of molecules

S(g) gt S(l) gt S(s)

ChemicalThermodynamics

Third Law of Thermodynamics

The entropy (S) of a pure crystalline substance at absolute zero (-273degC) is 0

ChemicalThermodynamics

Standard Entropiesbull Standard entropies tend to increase with increasing

molar mass

bull Larger and more complex molecules have greater entropies (greater ways to execute molecular motions)

EntropyampMolecuarSize EntropyampTempC7H15 500 K S=921JnK vs 200 K

ChemicalThermodynamics

Absolute Entropy (S)

- 237degC (0 K) S = 0

Standard Entropy (S˚)

25degC (298 K) S =

dT298

0 TC

T

TCS

K 298T

0T

TTC

TTmc

T

q S

Calculate the sum of all the infinitesimally small changes in entropy as T varies from T=0 T= 298 by taking its Integral

Standard Entropies (298 K) from Absolute Entropies (0K)

Sdeg

Temp (K)

Solid Liquid Gas

Hdegfus

Hdegvap

q = mcT

q = mcT

q = mcT

298

S

ChemicalThermodynamics

Entropy Changes in the System

where n and m are the coefficients in the balanced chemical equation

oreactants

oproducts

o298 SmSnS

Sdegsyst = Sdegrxn T

Entropy changes for a reaction (= system) can be estimated in a manner analogous to that by which H is estimated

ChemicalThermodynamics

Problem Calculate the standard entropy changes for the following reaction at 25oC

N2 (g) + 3 H2 (g) 2 NH3 (g)

Sdeg = nSdeg(prod) - mSdeg(react)

Sdeg = - 1983 J

2(1925) ndash [(1915)+3(1306)]

Entropy Changes in the System

ChemicalThermodynamics

oreactants

oproducts

o298 S S S

Thermodynamic Changes in Systems (Chem Reactions)

Appendix 1 (CHM 1046 Module) notice Sdeg is in J not kJ

Grxn = Gf (products) Gf (reactants)

Hrxn = Hf (products) - Hf (reactants)

ChemicalThermodynamics

Entropy Changes in the Surroundings

bull Heat (q) that flows into or out of the system changes the entropy of the surroundings

Ssurr prop - (qsys)bull For an isothermal process

Ssurr= (qsys)T

bull At constant pressure qsys is simply H for the system

System

q

q

qq

q

q

q

Ssurr= Hsys

TSurroundings

What in a chemical reaction causes entropy changes in the surroundings

ChemicalThermodynamics

Entropy Change in the Universe

K 298

1000 692( kJ) Jxmol kJ

Problem Calculate the Suniv for the synthesis of ammonia 25oC

N2 (g) + 3 H2 (g) 2 NH3 (g) Hdegrxn = - 926 kJmol

Ssurr =-Hsys

T

Ssurr = 311 JKmol

Suniv = Ssyst or rxn + Ssurr

nS(prod) - mS(react)

Sdegsyst = - 199 JKmiddotmol

2(1925) ndash [(1915)+3(1306)]

Suniv = - 1983 JKmiddotmol + 311 JKmol

Suniv = 113 JKmol

ChemicalThermodynamics

Entropy Change in the Universe

bull ThenSuniv = Ssyst + Hsystem

T

Suniv = Ssyst or rxn + Ssurr

Ssurr =-Hsys

Tbull Since

TSuniv = Hsyst TSsyst

TSuniv is defined as the Gibbs (free) Energy G

TSuniv = TSsyst + Hsyst

J Willard Gibbs USA 1839-1903

Multiplying both sides by T

ChemicalThermodynamics

bull When Suniv is positive G is negative

bull When G is negative the process is spontaneous

Gibbs Free Energy (G)

Gibbs Energy (-TΔS) measures the useful or process-initiating work obtainable from an isothermal isobaric thermodynamic system Technically the Gibbs free energy is the maximum amount of non-expansion work which can be extracted from a closed system or this maximum can be attained only in a completely reversible process

Guniv = Hsys TSsysTSuniv =

ChemicalThermodynamics

Free Energy Changes

At temperatures other than 25degC

Gdeg = H TS

How does G change with temperature

bull There are two parts to the free energy equation Hmdash the enthalpy term TS mdash the entropy term

bull The temperature dependence of free energy then comes from the entropy term

ChemicalThermodynamics

Spontaneity Enthalpy amp Entropy

Gdeg = H TS

Spontaneous all T

NonSpontaneous all T

Spontaneous high TSpontaneous low T

ChemicalThermodynamics

Spontaneity Enthalpy amp Entropy

Entropy Driven Reactions

Entropy amp Enthalpy Driven Reaction

Enthalpy Driven Reaction

Na2CO3(s) + HCl(aq) NaCl(aq) + CO2 (g)

2 H2(g) + O2 (g) 2 H2O(g)

NH4NO3(s) NH4+

(aq) + NO3-(aq)

n = 2-3 = -1

S = +H = +

G = H( TS)

EntropySyst+SurrFormationOfWater

(-TS)

(-TS)

(+TS)H = - S = -

H = - S = +

Enthalpy EntropyH2O

ChemicalThermodynamics

ProblemsGdeg = HT(S)

(-763)

ndash (-804)

+41

(3549)

ndash (2219)

+1330

Gdeg = H TS = (1313kJ) T(133kJ)

T = 987

TiCl4(l) TiCl4(g)

(-T)Reactant

Product

ChemicalThermodynamics

Standard Free Energy Changes

Analogous to standard enthalpies of formation are standard free energies of formation G

f

G = nG(products) mGf (reactants)f

where n and m are the stoichiometric coefficients

ChemicalThermodynamics

Standard Free Energy Changes

12 CO2(g) + 6 H2O(g)2 C6H6 (l) + 15 O2 (g)

Grxn = nG(prod) mG(react)f

Calculate the standard free energy changes for the above reaction 25 degC

f

[12(-394) + 6(-229)] ndash [2(125) + 15 (0)]

ndash [2 C6H6 (l) + 15 O2(g)][12 CO2(g) + 6 H2O(g)]

Grxn = - 6352 Jmol K

Standard Molar Gibbs Energy of Formation (Gdegf)

CO2 (g) -394

H2O (g) -229

C6H6 (l) 125

ChemicalThermodynamics

Fourth Law of Thermodynamics EmergenceComplex emergent systems spontaneously (-G) arise when energy flows through a collection of many interacting particles resulting in new patterns of complex behaviors that are much more than the sum of the individual parts (+S)

The formation of these complex patterns in emergent systems is more efficient in the dissipation of energy (-H) thus speeds up the increase of entropy in the universe

G = H -TSA precise definition of emergence and a useful mathematical formulation of this phenomenon remains elusive

C f [n i E(t)]Examples cells forming living organisms stars forming galaxies neurons forming conscious brain

ChemicalThermodynamics

ChemicalThermodynamics

ChemicalThermodynamics

ChemicalThermodynamics

ChemicalThermodynamics

ChemicalThermodynamics

ChemicalThermodynamics

2002 B

ChemicalThermodynamics

ChemicalThermodynamics

ChemicalThermodynamics

2003 A

ChemicalThermodynamics

ChemicalThermodynamics

2004 A

ChemicalThermodynamics

ChemicalThermodynamics

ChemicalThermodynamics

2004 B

ChemicalThermodynamics

ChemicalThermodynamics

2005 A

ChemicalThermodynamics

ChemicalThermodynamics

2006 (B)

ChemicalThermodynamics

ChemicalThermodynamics

ChemicalThermodynamics

2007 (A)

ChemicalThermodynamics

ChemicalThermodynamics

  • Unit 14 Chemical Thermodynamics
  • First Law of Thermodynamics
  • Second Law of Thermodynamics
  • Spontaneous Processes
  • Slide 5
  • Spontaneity
  • Irreversible Processes
  • Entropy (S)
  • Slide 9
  • Second Law of Thermodynamics
  • Slide 11
  • Entropy on the Molecular Scale
  • Slide 13
  • Entropy Changes
  • Third Law of Thermodynamics
  • Standard Entropies
  • Standard Entropies (298 K) from Absolute Entropies (0K)
  • Entropy Changes in the System
  • Slide 19
  • Thermodynamic Changes in Systems (Chem Reactions)
  • Entropy Changes in the Surroundings
  • Entropy Change in the Universe
  • Slide 23
  • Gibbs Free Energy (G)
  • Free Energy Changes
  • Spontaneity Enthalpy amp Entropy
  • Slide 27
  • Problems
  • Standard Free Energy Changes
  • Slide 30
  • Fourth Law of Thermodynamics Emergence
  • Slide 32
  • Slide 33
  • Slide 34
  • Slide 35
  • Slide 36
  • Slide 37
  • Slide 38
  • Slide 39
  • Slide 40
  • Slide 41
  • Slide 42
  • Slide 43
  • Slide 44
  • Slide 45
  • Slide 46
  • Slide 47
  • Slide 48
  • Slide 49
  • 2006 (B)
  • Slide 51
  • Slide 52
  • Slide 53
  • Slide 54
  • Slide 55
Page 13: Unit 14: Chemical Thermodynamics

ChemicalThermodynamics

Entropy on the Molecular Scale

bull The number of microstates (W) and therefore the entropy (S) tends to increase with increases in which variableshellip

Temperature (T)

Volume (V)

The number of independently moving molecules ()

S = k ln Whellipwhere k is the Boltzmann constant 138 1023 JK

ChemicalThermodynamics

Entropy Changes

CaCl2 (s) Ca 2+(aq) + 2Cl-(aq)

H2O

H2O (l) H2O(g)Heat

2 H2O (l) 2 H2 (g) + O2(g)Electricity

16 CO2(g) + 18 H2O(g)2 C8H18 (l) + 25 O2 (g)

gas= 34-25 = +92 = 45 C8H18

bull In which of the following does Entropy increase amp WHYhelliphellipGases are formed from liquids and solids

Liquids or solutions are formed from solids

The number of gas molecules (or moles) increasesEntropySolutionsKMnO4(aq)

EntropyampPhaseOfMatter

bull Entropy increases with the freedom of motion of molecules

S(g) gt S(l) gt S(s)

ChemicalThermodynamics

Third Law of Thermodynamics

The entropy (S) of a pure crystalline substance at absolute zero (-273degC) is 0

ChemicalThermodynamics

Standard Entropiesbull Standard entropies tend to increase with increasing

molar mass

bull Larger and more complex molecules have greater entropies (greater ways to execute molecular motions)

EntropyampMolecuarSize EntropyampTempC7H15 500 K S=921JnK vs 200 K

ChemicalThermodynamics

Absolute Entropy (S)

- 237degC (0 K) S = 0

Standard Entropy (S˚)

25degC (298 K) S =

dT298

0 TC

T

TCS

K 298T

0T

TTC

TTmc

T

q S

Calculate the sum of all the infinitesimally small changes in entropy as T varies from T=0 T= 298 by taking its Integral

Standard Entropies (298 K) from Absolute Entropies (0K)

Sdeg

Temp (K)

Solid Liquid Gas

Hdegfus

Hdegvap

q = mcT

q = mcT

q = mcT

298

S

ChemicalThermodynamics

Entropy Changes in the System

where n and m are the coefficients in the balanced chemical equation

oreactants

oproducts

o298 SmSnS

Sdegsyst = Sdegrxn T

Entropy changes for a reaction (= system) can be estimated in a manner analogous to that by which H is estimated

ChemicalThermodynamics

Problem Calculate the standard entropy changes for the following reaction at 25oC

N2 (g) + 3 H2 (g) 2 NH3 (g)

Sdeg = nSdeg(prod) - mSdeg(react)

Sdeg = - 1983 J

2(1925) ndash [(1915)+3(1306)]

Entropy Changes in the System

ChemicalThermodynamics

oreactants

oproducts

o298 S S S

Thermodynamic Changes in Systems (Chem Reactions)

Appendix 1 (CHM 1046 Module) notice Sdeg is in J not kJ

Grxn = Gf (products) Gf (reactants)

Hrxn = Hf (products) - Hf (reactants)

ChemicalThermodynamics

Entropy Changes in the Surroundings

bull Heat (q) that flows into or out of the system changes the entropy of the surroundings

Ssurr prop - (qsys)bull For an isothermal process

Ssurr= (qsys)T

bull At constant pressure qsys is simply H for the system

System

q

q

qq

q

q

q

Ssurr= Hsys

TSurroundings

What in a chemical reaction causes entropy changes in the surroundings

ChemicalThermodynamics

Entropy Change in the Universe

K 298

1000 692( kJ) Jxmol kJ

Problem Calculate the Suniv for the synthesis of ammonia 25oC

N2 (g) + 3 H2 (g) 2 NH3 (g) Hdegrxn = - 926 kJmol

Ssurr =-Hsys

T

Ssurr = 311 JKmol

Suniv = Ssyst or rxn + Ssurr

nS(prod) - mS(react)

Sdegsyst = - 199 JKmiddotmol

2(1925) ndash [(1915)+3(1306)]

Suniv = - 1983 JKmiddotmol + 311 JKmol

Suniv = 113 JKmol

ChemicalThermodynamics

Entropy Change in the Universe

bull ThenSuniv = Ssyst + Hsystem

T

Suniv = Ssyst or rxn + Ssurr

Ssurr =-Hsys

Tbull Since

TSuniv = Hsyst TSsyst

TSuniv is defined as the Gibbs (free) Energy G

TSuniv = TSsyst + Hsyst

J Willard Gibbs USA 1839-1903

Multiplying both sides by T

ChemicalThermodynamics

bull When Suniv is positive G is negative

bull When G is negative the process is spontaneous

Gibbs Free Energy (G)

Gibbs Energy (-TΔS) measures the useful or process-initiating work obtainable from an isothermal isobaric thermodynamic system Technically the Gibbs free energy is the maximum amount of non-expansion work which can be extracted from a closed system or this maximum can be attained only in a completely reversible process

Guniv = Hsys TSsysTSuniv =

ChemicalThermodynamics

Free Energy Changes

At temperatures other than 25degC

Gdeg = H TS

How does G change with temperature

bull There are two parts to the free energy equation Hmdash the enthalpy term TS mdash the entropy term

bull The temperature dependence of free energy then comes from the entropy term

ChemicalThermodynamics

Spontaneity Enthalpy amp Entropy

Gdeg = H TS

Spontaneous all T

NonSpontaneous all T

Spontaneous high TSpontaneous low T

ChemicalThermodynamics

Spontaneity Enthalpy amp Entropy

Entropy Driven Reactions

Entropy amp Enthalpy Driven Reaction

Enthalpy Driven Reaction

Na2CO3(s) + HCl(aq) NaCl(aq) + CO2 (g)

2 H2(g) + O2 (g) 2 H2O(g)

NH4NO3(s) NH4+

(aq) + NO3-(aq)

n = 2-3 = -1

S = +H = +

G = H( TS)

EntropySyst+SurrFormationOfWater

(-TS)

(-TS)

(+TS)H = - S = -

H = - S = +

Enthalpy EntropyH2O

ChemicalThermodynamics

ProblemsGdeg = HT(S)

(-763)

ndash (-804)

+41

(3549)

ndash (2219)

+1330

Gdeg = H TS = (1313kJ) T(133kJ)

T = 987

TiCl4(l) TiCl4(g)

(-T)Reactant

Product

ChemicalThermodynamics

Standard Free Energy Changes

Analogous to standard enthalpies of formation are standard free energies of formation G

f

G = nG(products) mGf (reactants)f

where n and m are the stoichiometric coefficients

ChemicalThermodynamics

Standard Free Energy Changes

12 CO2(g) + 6 H2O(g)2 C6H6 (l) + 15 O2 (g)

Grxn = nG(prod) mG(react)f

Calculate the standard free energy changes for the above reaction 25 degC

f

[12(-394) + 6(-229)] ndash [2(125) + 15 (0)]

ndash [2 C6H6 (l) + 15 O2(g)][12 CO2(g) + 6 H2O(g)]

Grxn = - 6352 Jmol K

Standard Molar Gibbs Energy of Formation (Gdegf)

CO2 (g) -394

H2O (g) -229

C6H6 (l) 125

ChemicalThermodynamics

Fourth Law of Thermodynamics EmergenceComplex emergent systems spontaneously (-G) arise when energy flows through a collection of many interacting particles resulting in new patterns of complex behaviors that are much more than the sum of the individual parts (+S)

The formation of these complex patterns in emergent systems is more efficient in the dissipation of energy (-H) thus speeds up the increase of entropy in the universe

G = H -TSA precise definition of emergence and a useful mathematical formulation of this phenomenon remains elusive

C f [n i E(t)]Examples cells forming living organisms stars forming galaxies neurons forming conscious brain

ChemicalThermodynamics

ChemicalThermodynamics

ChemicalThermodynamics

ChemicalThermodynamics

ChemicalThermodynamics

ChemicalThermodynamics

ChemicalThermodynamics

2002 B

ChemicalThermodynamics

ChemicalThermodynamics

ChemicalThermodynamics

2003 A

ChemicalThermodynamics

ChemicalThermodynamics

2004 A

ChemicalThermodynamics

ChemicalThermodynamics

ChemicalThermodynamics

2004 B

ChemicalThermodynamics

ChemicalThermodynamics

2005 A

ChemicalThermodynamics

ChemicalThermodynamics

2006 (B)

ChemicalThermodynamics

ChemicalThermodynamics

ChemicalThermodynamics

2007 (A)

ChemicalThermodynamics

ChemicalThermodynamics

  • Unit 14 Chemical Thermodynamics
  • First Law of Thermodynamics
  • Second Law of Thermodynamics
  • Spontaneous Processes
  • Slide 5
  • Spontaneity
  • Irreversible Processes
  • Entropy (S)
  • Slide 9
  • Second Law of Thermodynamics
  • Slide 11
  • Entropy on the Molecular Scale
  • Slide 13
  • Entropy Changes
  • Third Law of Thermodynamics
  • Standard Entropies
  • Standard Entropies (298 K) from Absolute Entropies (0K)
  • Entropy Changes in the System
  • Slide 19
  • Thermodynamic Changes in Systems (Chem Reactions)
  • Entropy Changes in the Surroundings
  • Entropy Change in the Universe
  • Slide 23
  • Gibbs Free Energy (G)
  • Free Energy Changes
  • Spontaneity Enthalpy amp Entropy
  • Slide 27
  • Problems
  • Standard Free Energy Changes
  • Slide 30
  • Fourth Law of Thermodynamics Emergence
  • Slide 32
  • Slide 33
  • Slide 34
  • Slide 35
  • Slide 36
  • Slide 37
  • Slide 38
  • Slide 39
  • Slide 40
  • Slide 41
  • Slide 42
  • Slide 43
  • Slide 44
  • Slide 45
  • Slide 46
  • Slide 47
  • Slide 48
  • Slide 49
  • 2006 (B)
  • Slide 51
  • Slide 52
  • Slide 53
  • Slide 54
  • Slide 55
Page 14: Unit 14: Chemical Thermodynamics

ChemicalThermodynamics

Entropy Changes

CaCl2 (s) Ca 2+(aq) + 2Cl-(aq)

H2O

H2O (l) H2O(g)Heat

2 H2O (l) 2 H2 (g) + O2(g)Electricity

16 CO2(g) + 18 H2O(g)2 C8H18 (l) + 25 O2 (g)

gas= 34-25 = +92 = 45 C8H18

bull In which of the following does Entropy increase amp WHYhelliphellipGases are formed from liquids and solids

Liquids or solutions are formed from solids

The number of gas molecules (or moles) increasesEntropySolutionsKMnO4(aq)

EntropyampPhaseOfMatter

bull Entropy increases with the freedom of motion of molecules

S(g) gt S(l) gt S(s)

ChemicalThermodynamics

Third Law of Thermodynamics

The entropy (S) of a pure crystalline substance at absolute zero (-273degC) is 0

ChemicalThermodynamics

Standard Entropiesbull Standard entropies tend to increase with increasing

molar mass

bull Larger and more complex molecules have greater entropies (greater ways to execute molecular motions)

EntropyampMolecuarSize EntropyampTempC7H15 500 K S=921JnK vs 200 K

ChemicalThermodynamics

Absolute Entropy (S)

- 237degC (0 K) S = 0

Standard Entropy (S˚)

25degC (298 K) S =

dT298

0 TC

T

TCS

K 298T

0T

TTC

TTmc

T

q S

Calculate the sum of all the infinitesimally small changes in entropy as T varies from T=0 T= 298 by taking its Integral

Standard Entropies (298 K) from Absolute Entropies (0K)

Sdeg

Temp (K)

Solid Liquid Gas

Hdegfus

Hdegvap

q = mcT

q = mcT

q = mcT

298

S

ChemicalThermodynamics

Entropy Changes in the System

where n and m are the coefficients in the balanced chemical equation

oreactants

oproducts

o298 SmSnS

Sdegsyst = Sdegrxn T

Entropy changes for a reaction (= system) can be estimated in a manner analogous to that by which H is estimated

ChemicalThermodynamics

Problem Calculate the standard entropy changes for the following reaction at 25oC

N2 (g) + 3 H2 (g) 2 NH3 (g)

Sdeg = nSdeg(prod) - mSdeg(react)

Sdeg = - 1983 J

2(1925) ndash [(1915)+3(1306)]

Entropy Changes in the System

ChemicalThermodynamics

oreactants

oproducts

o298 S S S

Thermodynamic Changes in Systems (Chem Reactions)

Appendix 1 (CHM 1046 Module) notice Sdeg is in J not kJ

Grxn = Gf (products) Gf (reactants)

Hrxn = Hf (products) - Hf (reactants)

ChemicalThermodynamics

Entropy Changes in the Surroundings

bull Heat (q) that flows into or out of the system changes the entropy of the surroundings

Ssurr prop - (qsys)bull For an isothermal process

Ssurr= (qsys)T

bull At constant pressure qsys is simply H for the system

System

q

q

qq

q

q

q

Ssurr= Hsys

TSurroundings

What in a chemical reaction causes entropy changes in the surroundings

ChemicalThermodynamics

Entropy Change in the Universe

K 298

1000 692( kJ) Jxmol kJ

Problem Calculate the Suniv for the synthesis of ammonia 25oC

N2 (g) + 3 H2 (g) 2 NH3 (g) Hdegrxn = - 926 kJmol

Ssurr =-Hsys

T

Ssurr = 311 JKmol

Suniv = Ssyst or rxn + Ssurr

nS(prod) - mS(react)

Sdegsyst = - 199 JKmiddotmol

2(1925) ndash [(1915)+3(1306)]

Suniv = - 1983 JKmiddotmol + 311 JKmol

Suniv = 113 JKmol

ChemicalThermodynamics

Entropy Change in the Universe

bull ThenSuniv = Ssyst + Hsystem

T

Suniv = Ssyst or rxn + Ssurr

Ssurr =-Hsys

Tbull Since

TSuniv = Hsyst TSsyst

TSuniv is defined as the Gibbs (free) Energy G

TSuniv = TSsyst + Hsyst

J Willard Gibbs USA 1839-1903

Multiplying both sides by T

ChemicalThermodynamics

bull When Suniv is positive G is negative

bull When G is negative the process is spontaneous

Gibbs Free Energy (G)

Gibbs Energy (-TΔS) measures the useful or process-initiating work obtainable from an isothermal isobaric thermodynamic system Technically the Gibbs free energy is the maximum amount of non-expansion work which can be extracted from a closed system or this maximum can be attained only in a completely reversible process

Guniv = Hsys TSsysTSuniv =

ChemicalThermodynamics

Free Energy Changes

At temperatures other than 25degC

Gdeg = H TS

How does G change with temperature

bull There are two parts to the free energy equation Hmdash the enthalpy term TS mdash the entropy term

bull The temperature dependence of free energy then comes from the entropy term

ChemicalThermodynamics

Spontaneity Enthalpy amp Entropy

Gdeg = H TS

Spontaneous all T

NonSpontaneous all T

Spontaneous high TSpontaneous low T

ChemicalThermodynamics

Spontaneity Enthalpy amp Entropy

Entropy Driven Reactions

Entropy amp Enthalpy Driven Reaction

Enthalpy Driven Reaction

Na2CO3(s) + HCl(aq) NaCl(aq) + CO2 (g)

2 H2(g) + O2 (g) 2 H2O(g)

NH4NO3(s) NH4+

(aq) + NO3-(aq)

n = 2-3 = -1

S = +H = +

G = H( TS)

EntropySyst+SurrFormationOfWater

(-TS)

(-TS)

(+TS)H = - S = -

H = - S = +

Enthalpy EntropyH2O

ChemicalThermodynamics

ProblemsGdeg = HT(S)

(-763)

ndash (-804)

+41

(3549)

ndash (2219)

+1330

Gdeg = H TS = (1313kJ) T(133kJ)

T = 987

TiCl4(l) TiCl4(g)

(-T)Reactant

Product

ChemicalThermodynamics

Standard Free Energy Changes

Analogous to standard enthalpies of formation are standard free energies of formation G

f

G = nG(products) mGf (reactants)f

where n and m are the stoichiometric coefficients

ChemicalThermodynamics

Standard Free Energy Changes

12 CO2(g) + 6 H2O(g)2 C6H6 (l) + 15 O2 (g)

Grxn = nG(prod) mG(react)f

Calculate the standard free energy changes for the above reaction 25 degC

f

[12(-394) + 6(-229)] ndash [2(125) + 15 (0)]

ndash [2 C6H6 (l) + 15 O2(g)][12 CO2(g) + 6 H2O(g)]

Grxn = - 6352 Jmol K

Standard Molar Gibbs Energy of Formation (Gdegf)

CO2 (g) -394

H2O (g) -229

C6H6 (l) 125

ChemicalThermodynamics

Fourth Law of Thermodynamics EmergenceComplex emergent systems spontaneously (-G) arise when energy flows through a collection of many interacting particles resulting in new patterns of complex behaviors that are much more than the sum of the individual parts (+S)

The formation of these complex patterns in emergent systems is more efficient in the dissipation of energy (-H) thus speeds up the increase of entropy in the universe

G = H -TSA precise definition of emergence and a useful mathematical formulation of this phenomenon remains elusive

C f [n i E(t)]Examples cells forming living organisms stars forming galaxies neurons forming conscious brain

ChemicalThermodynamics

ChemicalThermodynamics

ChemicalThermodynamics

ChemicalThermodynamics

ChemicalThermodynamics

ChemicalThermodynamics

ChemicalThermodynamics

2002 B

ChemicalThermodynamics

ChemicalThermodynamics

ChemicalThermodynamics

2003 A

ChemicalThermodynamics

ChemicalThermodynamics

2004 A

ChemicalThermodynamics

ChemicalThermodynamics

ChemicalThermodynamics

2004 B

ChemicalThermodynamics

ChemicalThermodynamics

2005 A

ChemicalThermodynamics

ChemicalThermodynamics

2006 (B)

ChemicalThermodynamics

ChemicalThermodynamics

ChemicalThermodynamics

2007 (A)

ChemicalThermodynamics

ChemicalThermodynamics

  • Unit 14 Chemical Thermodynamics
  • First Law of Thermodynamics
  • Second Law of Thermodynamics
  • Spontaneous Processes
  • Slide 5
  • Spontaneity
  • Irreversible Processes
  • Entropy (S)
  • Slide 9
  • Second Law of Thermodynamics
  • Slide 11
  • Entropy on the Molecular Scale
  • Slide 13
  • Entropy Changes
  • Third Law of Thermodynamics
  • Standard Entropies
  • Standard Entropies (298 K) from Absolute Entropies (0K)
  • Entropy Changes in the System
  • Slide 19
  • Thermodynamic Changes in Systems (Chem Reactions)
  • Entropy Changes in the Surroundings
  • Entropy Change in the Universe
  • Slide 23
  • Gibbs Free Energy (G)
  • Free Energy Changes
  • Spontaneity Enthalpy amp Entropy
  • Slide 27
  • Problems
  • Standard Free Energy Changes
  • Slide 30
  • Fourth Law of Thermodynamics Emergence
  • Slide 32
  • Slide 33
  • Slide 34
  • Slide 35
  • Slide 36
  • Slide 37
  • Slide 38
  • Slide 39
  • Slide 40
  • Slide 41
  • Slide 42
  • Slide 43
  • Slide 44
  • Slide 45
  • Slide 46
  • Slide 47
  • Slide 48
  • Slide 49
  • 2006 (B)
  • Slide 51
  • Slide 52
  • Slide 53
  • Slide 54
  • Slide 55
Page 15: Unit 14: Chemical Thermodynamics

ChemicalThermodynamics

Third Law of Thermodynamics

The entropy (S) of a pure crystalline substance at absolute zero (-273degC) is 0

ChemicalThermodynamics

Standard Entropiesbull Standard entropies tend to increase with increasing

molar mass

bull Larger and more complex molecules have greater entropies (greater ways to execute molecular motions)

EntropyampMolecuarSize EntropyampTempC7H15 500 K S=921JnK vs 200 K

ChemicalThermodynamics

Absolute Entropy (S)

- 237degC (0 K) S = 0

Standard Entropy (S˚)

25degC (298 K) S =

dT298

0 TC

T

TCS

K 298T

0T

TTC

TTmc

T

q S

Calculate the sum of all the infinitesimally small changes in entropy as T varies from T=0 T= 298 by taking its Integral

Standard Entropies (298 K) from Absolute Entropies (0K)

Sdeg

Temp (K)

Solid Liquid Gas

Hdegfus

Hdegvap

q = mcT

q = mcT

q = mcT

298

S

ChemicalThermodynamics

Entropy Changes in the System

where n and m are the coefficients in the balanced chemical equation

oreactants

oproducts

o298 SmSnS

Sdegsyst = Sdegrxn T

Entropy changes for a reaction (= system) can be estimated in a manner analogous to that by which H is estimated

ChemicalThermodynamics

Problem Calculate the standard entropy changes for the following reaction at 25oC

N2 (g) + 3 H2 (g) 2 NH3 (g)

Sdeg = nSdeg(prod) - mSdeg(react)

Sdeg = - 1983 J

2(1925) ndash [(1915)+3(1306)]

Entropy Changes in the System

ChemicalThermodynamics

oreactants

oproducts

o298 S S S

Thermodynamic Changes in Systems (Chem Reactions)

Appendix 1 (CHM 1046 Module) notice Sdeg is in J not kJ

Grxn = Gf (products) Gf (reactants)

Hrxn = Hf (products) - Hf (reactants)

ChemicalThermodynamics

Entropy Changes in the Surroundings

bull Heat (q) that flows into or out of the system changes the entropy of the surroundings

Ssurr prop - (qsys)bull For an isothermal process

Ssurr= (qsys)T

bull At constant pressure qsys is simply H for the system

System

q

q

qq

q

q

q

Ssurr= Hsys

TSurroundings

What in a chemical reaction causes entropy changes in the surroundings

ChemicalThermodynamics

Entropy Change in the Universe

K 298

1000 692( kJ) Jxmol kJ

Problem Calculate the Suniv for the synthesis of ammonia 25oC

N2 (g) + 3 H2 (g) 2 NH3 (g) Hdegrxn = - 926 kJmol

Ssurr =-Hsys

T

Ssurr = 311 JKmol

Suniv = Ssyst or rxn + Ssurr

nS(prod) - mS(react)

Sdegsyst = - 199 JKmiddotmol

2(1925) ndash [(1915)+3(1306)]

Suniv = - 1983 JKmiddotmol + 311 JKmol

Suniv = 113 JKmol

ChemicalThermodynamics

Entropy Change in the Universe

bull ThenSuniv = Ssyst + Hsystem

T

Suniv = Ssyst or rxn + Ssurr

Ssurr =-Hsys

Tbull Since

TSuniv = Hsyst TSsyst

TSuniv is defined as the Gibbs (free) Energy G

TSuniv = TSsyst + Hsyst

J Willard Gibbs USA 1839-1903

Multiplying both sides by T

ChemicalThermodynamics

bull When Suniv is positive G is negative

bull When G is negative the process is spontaneous

Gibbs Free Energy (G)

Gibbs Energy (-TΔS) measures the useful or process-initiating work obtainable from an isothermal isobaric thermodynamic system Technically the Gibbs free energy is the maximum amount of non-expansion work which can be extracted from a closed system or this maximum can be attained only in a completely reversible process

Guniv = Hsys TSsysTSuniv =

ChemicalThermodynamics

Free Energy Changes

At temperatures other than 25degC

Gdeg = H TS

How does G change with temperature

bull There are two parts to the free energy equation Hmdash the enthalpy term TS mdash the entropy term

bull The temperature dependence of free energy then comes from the entropy term

ChemicalThermodynamics

Spontaneity Enthalpy amp Entropy

Gdeg = H TS

Spontaneous all T

NonSpontaneous all T

Spontaneous high TSpontaneous low T

ChemicalThermodynamics

Spontaneity Enthalpy amp Entropy

Entropy Driven Reactions

Entropy amp Enthalpy Driven Reaction

Enthalpy Driven Reaction

Na2CO3(s) + HCl(aq) NaCl(aq) + CO2 (g)

2 H2(g) + O2 (g) 2 H2O(g)

NH4NO3(s) NH4+

(aq) + NO3-(aq)

n = 2-3 = -1

S = +H = +

G = H( TS)

EntropySyst+SurrFormationOfWater

(-TS)

(-TS)

(+TS)H = - S = -

H = - S = +

Enthalpy EntropyH2O

ChemicalThermodynamics

ProblemsGdeg = HT(S)

(-763)

ndash (-804)

+41

(3549)

ndash (2219)

+1330

Gdeg = H TS = (1313kJ) T(133kJ)

T = 987

TiCl4(l) TiCl4(g)

(-T)Reactant

Product

ChemicalThermodynamics

Standard Free Energy Changes

Analogous to standard enthalpies of formation are standard free energies of formation G

f

G = nG(products) mGf (reactants)f

where n and m are the stoichiometric coefficients

ChemicalThermodynamics

Standard Free Energy Changes

12 CO2(g) + 6 H2O(g)2 C6H6 (l) + 15 O2 (g)

Grxn = nG(prod) mG(react)f

Calculate the standard free energy changes for the above reaction 25 degC

f

[12(-394) + 6(-229)] ndash [2(125) + 15 (0)]

ndash [2 C6H6 (l) + 15 O2(g)][12 CO2(g) + 6 H2O(g)]

Grxn = - 6352 Jmol K

Standard Molar Gibbs Energy of Formation (Gdegf)

CO2 (g) -394

H2O (g) -229

C6H6 (l) 125

ChemicalThermodynamics

Fourth Law of Thermodynamics EmergenceComplex emergent systems spontaneously (-G) arise when energy flows through a collection of many interacting particles resulting in new patterns of complex behaviors that are much more than the sum of the individual parts (+S)

The formation of these complex patterns in emergent systems is more efficient in the dissipation of energy (-H) thus speeds up the increase of entropy in the universe

G = H -TSA precise definition of emergence and a useful mathematical formulation of this phenomenon remains elusive

C f [n i E(t)]Examples cells forming living organisms stars forming galaxies neurons forming conscious brain

ChemicalThermodynamics

ChemicalThermodynamics

ChemicalThermodynamics

ChemicalThermodynamics

ChemicalThermodynamics

ChemicalThermodynamics

ChemicalThermodynamics

2002 B

ChemicalThermodynamics

ChemicalThermodynamics

ChemicalThermodynamics

2003 A

ChemicalThermodynamics

ChemicalThermodynamics

2004 A

ChemicalThermodynamics

ChemicalThermodynamics

ChemicalThermodynamics

2004 B

ChemicalThermodynamics

ChemicalThermodynamics

2005 A

ChemicalThermodynamics

ChemicalThermodynamics

2006 (B)

ChemicalThermodynamics

ChemicalThermodynamics

ChemicalThermodynamics

2007 (A)

ChemicalThermodynamics

ChemicalThermodynamics

  • Unit 14 Chemical Thermodynamics
  • First Law of Thermodynamics
  • Second Law of Thermodynamics
  • Spontaneous Processes
  • Slide 5
  • Spontaneity
  • Irreversible Processes
  • Entropy (S)
  • Slide 9
  • Second Law of Thermodynamics
  • Slide 11
  • Entropy on the Molecular Scale
  • Slide 13
  • Entropy Changes
  • Third Law of Thermodynamics
  • Standard Entropies
  • Standard Entropies (298 K) from Absolute Entropies (0K)
  • Entropy Changes in the System
  • Slide 19
  • Thermodynamic Changes in Systems (Chem Reactions)
  • Entropy Changes in the Surroundings
  • Entropy Change in the Universe
  • Slide 23
  • Gibbs Free Energy (G)
  • Free Energy Changes
  • Spontaneity Enthalpy amp Entropy
  • Slide 27
  • Problems
  • Standard Free Energy Changes
  • Slide 30
  • Fourth Law of Thermodynamics Emergence
  • Slide 32
  • Slide 33
  • Slide 34
  • Slide 35
  • Slide 36
  • Slide 37
  • Slide 38
  • Slide 39
  • Slide 40
  • Slide 41
  • Slide 42
  • Slide 43
  • Slide 44
  • Slide 45
  • Slide 46
  • Slide 47
  • Slide 48
  • Slide 49
  • 2006 (B)
  • Slide 51
  • Slide 52
  • Slide 53
  • Slide 54
  • Slide 55
Page 16: Unit 14: Chemical Thermodynamics

ChemicalThermodynamics

Standard Entropiesbull Standard entropies tend to increase with increasing

molar mass

bull Larger and more complex molecules have greater entropies (greater ways to execute molecular motions)

EntropyampMolecuarSize EntropyampTempC7H15 500 K S=921JnK vs 200 K

ChemicalThermodynamics

Absolute Entropy (S)

- 237degC (0 K) S = 0

Standard Entropy (S˚)

25degC (298 K) S =

dT298

0 TC

T

TCS

K 298T

0T

TTC

TTmc

T

q S

Calculate the sum of all the infinitesimally small changes in entropy as T varies from T=0 T= 298 by taking its Integral

Standard Entropies (298 K) from Absolute Entropies (0K)

Sdeg

Temp (K)

Solid Liquid Gas

Hdegfus

Hdegvap

q = mcT

q = mcT

q = mcT

298

S

ChemicalThermodynamics

Entropy Changes in the System

where n and m are the coefficients in the balanced chemical equation

oreactants

oproducts

o298 SmSnS

Sdegsyst = Sdegrxn T

Entropy changes for a reaction (= system) can be estimated in a manner analogous to that by which H is estimated

ChemicalThermodynamics

Problem Calculate the standard entropy changes for the following reaction at 25oC

N2 (g) + 3 H2 (g) 2 NH3 (g)

Sdeg = nSdeg(prod) - mSdeg(react)

Sdeg = - 1983 J

2(1925) ndash [(1915)+3(1306)]

Entropy Changes in the System

ChemicalThermodynamics

oreactants

oproducts

o298 S S S

Thermodynamic Changes in Systems (Chem Reactions)

Appendix 1 (CHM 1046 Module) notice Sdeg is in J not kJ

Grxn = Gf (products) Gf (reactants)

Hrxn = Hf (products) - Hf (reactants)

ChemicalThermodynamics

Entropy Changes in the Surroundings

bull Heat (q) that flows into or out of the system changes the entropy of the surroundings

Ssurr prop - (qsys)bull For an isothermal process

Ssurr= (qsys)T

bull At constant pressure qsys is simply H for the system

System

q

q

qq

q

q

q

Ssurr= Hsys

TSurroundings

What in a chemical reaction causes entropy changes in the surroundings

ChemicalThermodynamics

Entropy Change in the Universe

K 298

1000 692( kJ) Jxmol kJ

Problem Calculate the Suniv for the synthesis of ammonia 25oC

N2 (g) + 3 H2 (g) 2 NH3 (g) Hdegrxn = - 926 kJmol

Ssurr =-Hsys

T

Ssurr = 311 JKmol

Suniv = Ssyst or rxn + Ssurr

nS(prod) - mS(react)

Sdegsyst = - 199 JKmiddotmol

2(1925) ndash [(1915)+3(1306)]

Suniv = - 1983 JKmiddotmol + 311 JKmol

Suniv = 113 JKmol

ChemicalThermodynamics

Entropy Change in the Universe

bull ThenSuniv = Ssyst + Hsystem

T

Suniv = Ssyst or rxn + Ssurr

Ssurr =-Hsys

Tbull Since

TSuniv = Hsyst TSsyst

TSuniv is defined as the Gibbs (free) Energy G

TSuniv = TSsyst + Hsyst

J Willard Gibbs USA 1839-1903

Multiplying both sides by T

ChemicalThermodynamics

bull When Suniv is positive G is negative

bull When G is negative the process is spontaneous

Gibbs Free Energy (G)

Gibbs Energy (-TΔS) measures the useful or process-initiating work obtainable from an isothermal isobaric thermodynamic system Technically the Gibbs free energy is the maximum amount of non-expansion work which can be extracted from a closed system or this maximum can be attained only in a completely reversible process

Guniv = Hsys TSsysTSuniv =

ChemicalThermodynamics

Free Energy Changes

At temperatures other than 25degC

Gdeg = H TS

How does G change with temperature

bull There are two parts to the free energy equation Hmdash the enthalpy term TS mdash the entropy term

bull The temperature dependence of free energy then comes from the entropy term

ChemicalThermodynamics

Spontaneity Enthalpy amp Entropy

Gdeg = H TS

Spontaneous all T

NonSpontaneous all T

Spontaneous high TSpontaneous low T

ChemicalThermodynamics

Spontaneity Enthalpy amp Entropy

Entropy Driven Reactions

Entropy amp Enthalpy Driven Reaction

Enthalpy Driven Reaction

Na2CO3(s) + HCl(aq) NaCl(aq) + CO2 (g)

2 H2(g) + O2 (g) 2 H2O(g)

NH4NO3(s) NH4+

(aq) + NO3-(aq)

n = 2-3 = -1

S = +H = +

G = H( TS)

EntropySyst+SurrFormationOfWater

(-TS)

(-TS)

(+TS)H = - S = -

H = - S = +

Enthalpy EntropyH2O

ChemicalThermodynamics

ProblemsGdeg = HT(S)

(-763)

ndash (-804)

+41

(3549)

ndash (2219)

+1330

Gdeg = H TS = (1313kJ) T(133kJ)

T = 987

TiCl4(l) TiCl4(g)

(-T)Reactant

Product

ChemicalThermodynamics

Standard Free Energy Changes

Analogous to standard enthalpies of formation are standard free energies of formation G

f

G = nG(products) mGf (reactants)f

where n and m are the stoichiometric coefficients

ChemicalThermodynamics

Standard Free Energy Changes

12 CO2(g) + 6 H2O(g)2 C6H6 (l) + 15 O2 (g)

Grxn = nG(prod) mG(react)f

Calculate the standard free energy changes for the above reaction 25 degC

f

[12(-394) + 6(-229)] ndash [2(125) + 15 (0)]

ndash [2 C6H6 (l) + 15 O2(g)][12 CO2(g) + 6 H2O(g)]

Grxn = - 6352 Jmol K

Standard Molar Gibbs Energy of Formation (Gdegf)

CO2 (g) -394

H2O (g) -229

C6H6 (l) 125

ChemicalThermodynamics

Fourth Law of Thermodynamics EmergenceComplex emergent systems spontaneously (-G) arise when energy flows through a collection of many interacting particles resulting in new patterns of complex behaviors that are much more than the sum of the individual parts (+S)

The formation of these complex patterns in emergent systems is more efficient in the dissipation of energy (-H) thus speeds up the increase of entropy in the universe

G = H -TSA precise definition of emergence and a useful mathematical formulation of this phenomenon remains elusive

C f [n i E(t)]Examples cells forming living organisms stars forming galaxies neurons forming conscious brain

ChemicalThermodynamics

ChemicalThermodynamics

ChemicalThermodynamics

ChemicalThermodynamics

ChemicalThermodynamics

ChemicalThermodynamics

ChemicalThermodynamics

2002 B

ChemicalThermodynamics

ChemicalThermodynamics

ChemicalThermodynamics

2003 A

ChemicalThermodynamics

ChemicalThermodynamics

2004 A

ChemicalThermodynamics

ChemicalThermodynamics

ChemicalThermodynamics

2004 B

ChemicalThermodynamics

ChemicalThermodynamics

2005 A

ChemicalThermodynamics

ChemicalThermodynamics

2006 (B)

ChemicalThermodynamics

ChemicalThermodynamics

ChemicalThermodynamics

2007 (A)

ChemicalThermodynamics

ChemicalThermodynamics

  • Unit 14 Chemical Thermodynamics
  • First Law of Thermodynamics
  • Second Law of Thermodynamics
  • Spontaneous Processes
  • Slide 5
  • Spontaneity
  • Irreversible Processes
  • Entropy (S)
  • Slide 9
  • Second Law of Thermodynamics
  • Slide 11
  • Entropy on the Molecular Scale
  • Slide 13
  • Entropy Changes
  • Third Law of Thermodynamics
  • Standard Entropies
  • Standard Entropies (298 K) from Absolute Entropies (0K)
  • Entropy Changes in the System
  • Slide 19
  • Thermodynamic Changes in Systems (Chem Reactions)
  • Entropy Changes in the Surroundings
  • Entropy Change in the Universe
  • Slide 23
  • Gibbs Free Energy (G)
  • Free Energy Changes
  • Spontaneity Enthalpy amp Entropy
  • Slide 27
  • Problems
  • Standard Free Energy Changes
  • Slide 30
  • Fourth Law of Thermodynamics Emergence
  • Slide 32
  • Slide 33
  • Slide 34
  • Slide 35
  • Slide 36
  • Slide 37
  • Slide 38
  • Slide 39
  • Slide 40
  • Slide 41
  • Slide 42
  • Slide 43
  • Slide 44
  • Slide 45
  • Slide 46
  • Slide 47
  • Slide 48
  • Slide 49
  • 2006 (B)
  • Slide 51
  • Slide 52
  • Slide 53
  • Slide 54
  • Slide 55
Page 17: Unit 14: Chemical Thermodynamics

ChemicalThermodynamics

Absolute Entropy (S)

- 237degC (0 K) S = 0

Standard Entropy (S˚)

25degC (298 K) S =

dT298

0 TC

T

TCS

K 298T

0T

TTC

TTmc

T

q S

Calculate the sum of all the infinitesimally small changes in entropy as T varies from T=0 T= 298 by taking its Integral

Standard Entropies (298 K) from Absolute Entropies (0K)

Sdeg

Temp (K)

Solid Liquid Gas

Hdegfus

Hdegvap

q = mcT

q = mcT

q = mcT

298

S

ChemicalThermodynamics

Entropy Changes in the System

where n and m are the coefficients in the balanced chemical equation

oreactants

oproducts

o298 SmSnS

Sdegsyst = Sdegrxn T

Entropy changes for a reaction (= system) can be estimated in a manner analogous to that by which H is estimated

ChemicalThermodynamics

Problem Calculate the standard entropy changes for the following reaction at 25oC

N2 (g) + 3 H2 (g) 2 NH3 (g)

Sdeg = nSdeg(prod) - mSdeg(react)

Sdeg = - 1983 J

2(1925) ndash [(1915)+3(1306)]

Entropy Changes in the System

ChemicalThermodynamics

oreactants

oproducts

o298 S S S

Thermodynamic Changes in Systems (Chem Reactions)

Appendix 1 (CHM 1046 Module) notice Sdeg is in J not kJ

Grxn = Gf (products) Gf (reactants)

Hrxn = Hf (products) - Hf (reactants)

ChemicalThermodynamics

Entropy Changes in the Surroundings

bull Heat (q) that flows into or out of the system changes the entropy of the surroundings

Ssurr prop - (qsys)bull For an isothermal process

Ssurr= (qsys)T

bull At constant pressure qsys is simply H for the system

System

q

q

qq

q

q

q

Ssurr= Hsys

TSurroundings

What in a chemical reaction causes entropy changes in the surroundings

ChemicalThermodynamics

Entropy Change in the Universe

K 298

1000 692( kJ) Jxmol kJ

Problem Calculate the Suniv for the synthesis of ammonia 25oC

N2 (g) + 3 H2 (g) 2 NH3 (g) Hdegrxn = - 926 kJmol

Ssurr =-Hsys

T

Ssurr = 311 JKmol

Suniv = Ssyst or rxn + Ssurr

nS(prod) - mS(react)

Sdegsyst = - 199 JKmiddotmol

2(1925) ndash [(1915)+3(1306)]

Suniv = - 1983 JKmiddotmol + 311 JKmol

Suniv = 113 JKmol

ChemicalThermodynamics

Entropy Change in the Universe

bull ThenSuniv = Ssyst + Hsystem

T

Suniv = Ssyst or rxn + Ssurr

Ssurr =-Hsys

Tbull Since

TSuniv = Hsyst TSsyst

TSuniv is defined as the Gibbs (free) Energy G

TSuniv = TSsyst + Hsyst

J Willard Gibbs USA 1839-1903

Multiplying both sides by T

ChemicalThermodynamics

bull When Suniv is positive G is negative

bull When G is negative the process is spontaneous

Gibbs Free Energy (G)

Gibbs Energy (-TΔS) measures the useful or process-initiating work obtainable from an isothermal isobaric thermodynamic system Technically the Gibbs free energy is the maximum amount of non-expansion work which can be extracted from a closed system or this maximum can be attained only in a completely reversible process

Guniv = Hsys TSsysTSuniv =

ChemicalThermodynamics

Free Energy Changes

At temperatures other than 25degC

Gdeg = H TS

How does G change with temperature

bull There are two parts to the free energy equation Hmdash the enthalpy term TS mdash the entropy term

bull The temperature dependence of free energy then comes from the entropy term

ChemicalThermodynamics

Spontaneity Enthalpy amp Entropy

Gdeg = H TS

Spontaneous all T

NonSpontaneous all T

Spontaneous high TSpontaneous low T

ChemicalThermodynamics

Spontaneity Enthalpy amp Entropy

Entropy Driven Reactions

Entropy amp Enthalpy Driven Reaction

Enthalpy Driven Reaction

Na2CO3(s) + HCl(aq) NaCl(aq) + CO2 (g)

2 H2(g) + O2 (g) 2 H2O(g)

NH4NO3(s) NH4+

(aq) + NO3-(aq)

n = 2-3 = -1

S = +H = +

G = H( TS)

EntropySyst+SurrFormationOfWater

(-TS)

(-TS)

(+TS)H = - S = -

H = - S = +

Enthalpy EntropyH2O

ChemicalThermodynamics

ProblemsGdeg = HT(S)

(-763)

ndash (-804)

+41

(3549)

ndash (2219)

+1330

Gdeg = H TS = (1313kJ) T(133kJ)

T = 987

TiCl4(l) TiCl4(g)

(-T)Reactant

Product

ChemicalThermodynamics

Standard Free Energy Changes

Analogous to standard enthalpies of formation are standard free energies of formation G

f

G = nG(products) mGf (reactants)f

where n and m are the stoichiometric coefficients

ChemicalThermodynamics

Standard Free Energy Changes

12 CO2(g) + 6 H2O(g)2 C6H6 (l) + 15 O2 (g)

Grxn = nG(prod) mG(react)f

Calculate the standard free energy changes for the above reaction 25 degC

f

[12(-394) + 6(-229)] ndash [2(125) + 15 (0)]

ndash [2 C6H6 (l) + 15 O2(g)][12 CO2(g) + 6 H2O(g)]

Grxn = - 6352 Jmol K

Standard Molar Gibbs Energy of Formation (Gdegf)

CO2 (g) -394

H2O (g) -229

C6H6 (l) 125

ChemicalThermodynamics

Fourth Law of Thermodynamics EmergenceComplex emergent systems spontaneously (-G) arise when energy flows through a collection of many interacting particles resulting in new patterns of complex behaviors that are much more than the sum of the individual parts (+S)

The formation of these complex patterns in emergent systems is more efficient in the dissipation of energy (-H) thus speeds up the increase of entropy in the universe

G = H -TSA precise definition of emergence and a useful mathematical formulation of this phenomenon remains elusive

C f [n i E(t)]Examples cells forming living organisms stars forming galaxies neurons forming conscious brain

ChemicalThermodynamics

ChemicalThermodynamics

ChemicalThermodynamics

ChemicalThermodynamics

ChemicalThermodynamics

ChemicalThermodynamics

ChemicalThermodynamics

2002 B

ChemicalThermodynamics

ChemicalThermodynamics

ChemicalThermodynamics

2003 A

ChemicalThermodynamics

ChemicalThermodynamics

2004 A

ChemicalThermodynamics

ChemicalThermodynamics

ChemicalThermodynamics

2004 B

ChemicalThermodynamics

ChemicalThermodynamics

2005 A

ChemicalThermodynamics

ChemicalThermodynamics

2006 (B)

ChemicalThermodynamics

ChemicalThermodynamics

ChemicalThermodynamics

2007 (A)

ChemicalThermodynamics

ChemicalThermodynamics

  • Unit 14 Chemical Thermodynamics
  • First Law of Thermodynamics
  • Second Law of Thermodynamics
  • Spontaneous Processes
  • Slide 5
  • Spontaneity
  • Irreversible Processes
  • Entropy (S)
  • Slide 9
  • Second Law of Thermodynamics
  • Slide 11
  • Entropy on the Molecular Scale
  • Slide 13
  • Entropy Changes
  • Third Law of Thermodynamics
  • Standard Entropies
  • Standard Entropies (298 K) from Absolute Entropies (0K)
  • Entropy Changes in the System
  • Slide 19
  • Thermodynamic Changes in Systems (Chem Reactions)
  • Entropy Changes in the Surroundings
  • Entropy Change in the Universe
  • Slide 23
  • Gibbs Free Energy (G)
  • Free Energy Changes
  • Spontaneity Enthalpy amp Entropy
  • Slide 27
  • Problems
  • Standard Free Energy Changes
  • Slide 30
  • Fourth Law of Thermodynamics Emergence
  • Slide 32
  • Slide 33
  • Slide 34
  • Slide 35
  • Slide 36
  • Slide 37
  • Slide 38
  • Slide 39
  • Slide 40
  • Slide 41
  • Slide 42
  • Slide 43
  • Slide 44
  • Slide 45
  • Slide 46
  • Slide 47
  • Slide 48
  • Slide 49
  • 2006 (B)
  • Slide 51
  • Slide 52
  • Slide 53
  • Slide 54
  • Slide 55
Page 18: Unit 14: Chemical Thermodynamics

ChemicalThermodynamics

Entropy Changes in the System

where n and m are the coefficients in the balanced chemical equation

oreactants

oproducts

o298 SmSnS

Sdegsyst = Sdegrxn T

Entropy changes for a reaction (= system) can be estimated in a manner analogous to that by which H is estimated

ChemicalThermodynamics

Problem Calculate the standard entropy changes for the following reaction at 25oC

N2 (g) + 3 H2 (g) 2 NH3 (g)

Sdeg = nSdeg(prod) - mSdeg(react)

Sdeg = - 1983 J

2(1925) ndash [(1915)+3(1306)]

Entropy Changes in the System

ChemicalThermodynamics

oreactants

oproducts

o298 S S S

Thermodynamic Changes in Systems (Chem Reactions)

Appendix 1 (CHM 1046 Module) notice Sdeg is in J not kJ

Grxn = Gf (products) Gf (reactants)

Hrxn = Hf (products) - Hf (reactants)

ChemicalThermodynamics

Entropy Changes in the Surroundings

bull Heat (q) that flows into or out of the system changes the entropy of the surroundings

Ssurr prop - (qsys)bull For an isothermal process

Ssurr= (qsys)T

bull At constant pressure qsys is simply H for the system

System

q

q

qq

q

q

q

Ssurr= Hsys

TSurroundings

What in a chemical reaction causes entropy changes in the surroundings

ChemicalThermodynamics

Entropy Change in the Universe

K 298

1000 692( kJ) Jxmol kJ

Problem Calculate the Suniv for the synthesis of ammonia 25oC

N2 (g) + 3 H2 (g) 2 NH3 (g) Hdegrxn = - 926 kJmol

Ssurr =-Hsys

T

Ssurr = 311 JKmol

Suniv = Ssyst or rxn + Ssurr

nS(prod) - mS(react)

Sdegsyst = - 199 JKmiddotmol

2(1925) ndash [(1915)+3(1306)]

Suniv = - 1983 JKmiddotmol + 311 JKmol

Suniv = 113 JKmol

ChemicalThermodynamics

Entropy Change in the Universe

bull ThenSuniv = Ssyst + Hsystem

T

Suniv = Ssyst or rxn + Ssurr

Ssurr =-Hsys

Tbull Since

TSuniv = Hsyst TSsyst

TSuniv is defined as the Gibbs (free) Energy G

TSuniv = TSsyst + Hsyst

J Willard Gibbs USA 1839-1903

Multiplying both sides by T

ChemicalThermodynamics

bull When Suniv is positive G is negative

bull When G is negative the process is spontaneous

Gibbs Free Energy (G)

Gibbs Energy (-TΔS) measures the useful or process-initiating work obtainable from an isothermal isobaric thermodynamic system Technically the Gibbs free energy is the maximum amount of non-expansion work which can be extracted from a closed system or this maximum can be attained only in a completely reversible process

Guniv = Hsys TSsysTSuniv =

ChemicalThermodynamics

Free Energy Changes

At temperatures other than 25degC

Gdeg = H TS

How does G change with temperature

bull There are two parts to the free energy equation Hmdash the enthalpy term TS mdash the entropy term

bull The temperature dependence of free energy then comes from the entropy term

ChemicalThermodynamics

Spontaneity Enthalpy amp Entropy

Gdeg = H TS

Spontaneous all T

NonSpontaneous all T

Spontaneous high TSpontaneous low T

ChemicalThermodynamics

Spontaneity Enthalpy amp Entropy

Entropy Driven Reactions

Entropy amp Enthalpy Driven Reaction

Enthalpy Driven Reaction

Na2CO3(s) + HCl(aq) NaCl(aq) + CO2 (g)

2 H2(g) + O2 (g) 2 H2O(g)

NH4NO3(s) NH4+

(aq) + NO3-(aq)

n = 2-3 = -1

S = +H = +

G = H( TS)

EntropySyst+SurrFormationOfWater

(-TS)

(-TS)

(+TS)H = - S = -

H = - S = +

Enthalpy EntropyH2O

ChemicalThermodynamics

ProblemsGdeg = HT(S)

(-763)

ndash (-804)

+41

(3549)

ndash (2219)

+1330

Gdeg = H TS = (1313kJ) T(133kJ)

T = 987

TiCl4(l) TiCl4(g)

(-T)Reactant

Product

ChemicalThermodynamics

Standard Free Energy Changes

Analogous to standard enthalpies of formation are standard free energies of formation G

f

G = nG(products) mGf (reactants)f

where n and m are the stoichiometric coefficients

ChemicalThermodynamics

Standard Free Energy Changes

12 CO2(g) + 6 H2O(g)2 C6H6 (l) + 15 O2 (g)

Grxn = nG(prod) mG(react)f

Calculate the standard free energy changes for the above reaction 25 degC

f

[12(-394) + 6(-229)] ndash [2(125) + 15 (0)]

ndash [2 C6H6 (l) + 15 O2(g)][12 CO2(g) + 6 H2O(g)]

Grxn = - 6352 Jmol K

Standard Molar Gibbs Energy of Formation (Gdegf)

CO2 (g) -394

H2O (g) -229

C6H6 (l) 125

ChemicalThermodynamics

Fourth Law of Thermodynamics EmergenceComplex emergent systems spontaneously (-G) arise when energy flows through a collection of many interacting particles resulting in new patterns of complex behaviors that are much more than the sum of the individual parts (+S)

The formation of these complex patterns in emergent systems is more efficient in the dissipation of energy (-H) thus speeds up the increase of entropy in the universe

G = H -TSA precise definition of emergence and a useful mathematical formulation of this phenomenon remains elusive

C f [n i E(t)]Examples cells forming living organisms stars forming galaxies neurons forming conscious brain

ChemicalThermodynamics

ChemicalThermodynamics

ChemicalThermodynamics

ChemicalThermodynamics

ChemicalThermodynamics

ChemicalThermodynamics

ChemicalThermodynamics

2002 B

ChemicalThermodynamics

ChemicalThermodynamics

ChemicalThermodynamics

2003 A

ChemicalThermodynamics

ChemicalThermodynamics

2004 A

ChemicalThermodynamics

ChemicalThermodynamics

ChemicalThermodynamics

2004 B

ChemicalThermodynamics

ChemicalThermodynamics

2005 A

ChemicalThermodynamics

ChemicalThermodynamics

2006 (B)

ChemicalThermodynamics

ChemicalThermodynamics

ChemicalThermodynamics

2007 (A)

ChemicalThermodynamics

ChemicalThermodynamics

  • Unit 14 Chemical Thermodynamics
  • First Law of Thermodynamics
  • Second Law of Thermodynamics
  • Spontaneous Processes
  • Slide 5
  • Spontaneity
  • Irreversible Processes
  • Entropy (S)
  • Slide 9
  • Second Law of Thermodynamics
  • Slide 11
  • Entropy on the Molecular Scale
  • Slide 13
  • Entropy Changes
  • Third Law of Thermodynamics
  • Standard Entropies
  • Standard Entropies (298 K) from Absolute Entropies (0K)
  • Entropy Changes in the System
  • Slide 19
  • Thermodynamic Changes in Systems (Chem Reactions)
  • Entropy Changes in the Surroundings
  • Entropy Change in the Universe
  • Slide 23
  • Gibbs Free Energy (G)
  • Free Energy Changes
  • Spontaneity Enthalpy amp Entropy
  • Slide 27
  • Problems
  • Standard Free Energy Changes
  • Slide 30
  • Fourth Law of Thermodynamics Emergence
  • Slide 32
  • Slide 33
  • Slide 34
  • Slide 35
  • Slide 36
  • Slide 37
  • Slide 38
  • Slide 39
  • Slide 40
  • Slide 41
  • Slide 42
  • Slide 43
  • Slide 44
  • Slide 45
  • Slide 46
  • Slide 47
  • Slide 48
  • Slide 49
  • 2006 (B)
  • Slide 51
  • Slide 52
  • Slide 53
  • Slide 54
  • Slide 55
Page 19: Unit 14: Chemical Thermodynamics

ChemicalThermodynamics

Problem Calculate the standard entropy changes for the following reaction at 25oC

N2 (g) + 3 H2 (g) 2 NH3 (g)

Sdeg = nSdeg(prod) - mSdeg(react)

Sdeg = - 1983 J

2(1925) ndash [(1915)+3(1306)]

Entropy Changes in the System

ChemicalThermodynamics

oreactants

oproducts

o298 S S S

Thermodynamic Changes in Systems (Chem Reactions)

Appendix 1 (CHM 1046 Module) notice Sdeg is in J not kJ

Grxn = Gf (products) Gf (reactants)

Hrxn = Hf (products) - Hf (reactants)

ChemicalThermodynamics

Entropy Changes in the Surroundings

bull Heat (q) that flows into or out of the system changes the entropy of the surroundings

Ssurr prop - (qsys)bull For an isothermal process

Ssurr= (qsys)T

bull At constant pressure qsys is simply H for the system

System

q

q

qq

q

q

q

Ssurr= Hsys

TSurroundings

What in a chemical reaction causes entropy changes in the surroundings

ChemicalThermodynamics

Entropy Change in the Universe

K 298

1000 692( kJ) Jxmol kJ

Problem Calculate the Suniv for the synthesis of ammonia 25oC

N2 (g) + 3 H2 (g) 2 NH3 (g) Hdegrxn = - 926 kJmol

Ssurr =-Hsys

T

Ssurr = 311 JKmol

Suniv = Ssyst or rxn + Ssurr

nS(prod) - mS(react)

Sdegsyst = - 199 JKmiddotmol

2(1925) ndash [(1915)+3(1306)]

Suniv = - 1983 JKmiddotmol + 311 JKmol

Suniv = 113 JKmol

ChemicalThermodynamics

Entropy Change in the Universe

bull ThenSuniv = Ssyst + Hsystem

T

Suniv = Ssyst or rxn + Ssurr

Ssurr =-Hsys

Tbull Since

TSuniv = Hsyst TSsyst

TSuniv is defined as the Gibbs (free) Energy G

TSuniv = TSsyst + Hsyst

J Willard Gibbs USA 1839-1903

Multiplying both sides by T

ChemicalThermodynamics

bull When Suniv is positive G is negative

bull When G is negative the process is spontaneous

Gibbs Free Energy (G)

Gibbs Energy (-TΔS) measures the useful or process-initiating work obtainable from an isothermal isobaric thermodynamic system Technically the Gibbs free energy is the maximum amount of non-expansion work which can be extracted from a closed system or this maximum can be attained only in a completely reversible process

Guniv = Hsys TSsysTSuniv =

ChemicalThermodynamics

Free Energy Changes

At temperatures other than 25degC

Gdeg = H TS

How does G change with temperature

bull There are two parts to the free energy equation Hmdash the enthalpy term TS mdash the entropy term

bull The temperature dependence of free energy then comes from the entropy term

ChemicalThermodynamics

Spontaneity Enthalpy amp Entropy

Gdeg = H TS

Spontaneous all T

NonSpontaneous all T

Spontaneous high TSpontaneous low T

ChemicalThermodynamics

Spontaneity Enthalpy amp Entropy

Entropy Driven Reactions

Entropy amp Enthalpy Driven Reaction

Enthalpy Driven Reaction

Na2CO3(s) + HCl(aq) NaCl(aq) + CO2 (g)

2 H2(g) + O2 (g) 2 H2O(g)

NH4NO3(s) NH4+

(aq) + NO3-(aq)

n = 2-3 = -1

S = +H = +

G = H( TS)

EntropySyst+SurrFormationOfWater

(-TS)

(-TS)

(+TS)H = - S = -

H = - S = +

Enthalpy EntropyH2O

ChemicalThermodynamics

ProblemsGdeg = HT(S)

(-763)

ndash (-804)

+41

(3549)

ndash (2219)

+1330

Gdeg = H TS = (1313kJ) T(133kJ)

T = 987

TiCl4(l) TiCl4(g)

(-T)Reactant

Product

ChemicalThermodynamics

Standard Free Energy Changes

Analogous to standard enthalpies of formation are standard free energies of formation G

f

G = nG(products) mGf (reactants)f

where n and m are the stoichiometric coefficients

ChemicalThermodynamics

Standard Free Energy Changes

12 CO2(g) + 6 H2O(g)2 C6H6 (l) + 15 O2 (g)

Grxn = nG(prod) mG(react)f

Calculate the standard free energy changes for the above reaction 25 degC

f

[12(-394) + 6(-229)] ndash [2(125) + 15 (0)]

ndash [2 C6H6 (l) + 15 O2(g)][12 CO2(g) + 6 H2O(g)]

Grxn = - 6352 Jmol K

Standard Molar Gibbs Energy of Formation (Gdegf)

CO2 (g) -394

H2O (g) -229

C6H6 (l) 125

ChemicalThermodynamics

Fourth Law of Thermodynamics EmergenceComplex emergent systems spontaneously (-G) arise when energy flows through a collection of many interacting particles resulting in new patterns of complex behaviors that are much more than the sum of the individual parts (+S)

The formation of these complex patterns in emergent systems is more efficient in the dissipation of energy (-H) thus speeds up the increase of entropy in the universe

G = H -TSA precise definition of emergence and a useful mathematical formulation of this phenomenon remains elusive

C f [n i E(t)]Examples cells forming living organisms stars forming galaxies neurons forming conscious brain

ChemicalThermodynamics

ChemicalThermodynamics

ChemicalThermodynamics

ChemicalThermodynamics

ChemicalThermodynamics

ChemicalThermodynamics

ChemicalThermodynamics

2002 B

ChemicalThermodynamics

ChemicalThermodynamics

ChemicalThermodynamics

2003 A

ChemicalThermodynamics

ChemicalThermodynamics

2004 A

ChemicalThermodynamics

ChemicalThermodynamics

ChemicalThermodynamics

2004 B

ChemicalThermodynamics

ChemicalThermodynamics

2005 A

ChemicalThermodynamics

ChemicalThermodynamics

2006 (B)

ChemicalThermodynamics

ChemicalThermodynamics

ChemicalThermodynamics

2007 (A)

ChemicalThermodynamics

ChemicalThermodynamics

  • Unit 14 Chemical Thermodynamics
  • First Law of Thermodynamics
  • Second Law of Thermodynamics
  • Spontaneous Processes
  • Slide 5
  • Spontaneity
  • Irreversible Processes
  • Entropy (S)
  • Slide 9
  • Second Law of Thermodynamics
  • Slide 11
  • Entropy on the Molecular Scale
  • Slide 13
  • Entropy Changes
  • Third Law of Thermodynamics
  • Standard Entropies
  • Standard Entropies (298 K) from Absolute Entropies (0K)
  • Entropy Changes in the System
  • Slide 19
  • Thermodynamic Changes in Systems (Chem Reactions)
  • Entropy Changes in the Surroundings
  • Entropy Change in the Universe
  • Slide 23
  • Gibbs Free Energy (G)
  • Free Energy Changes
  • Spontaneity Enthalpy amp Entropy
  • Slide 27
  • Problems
  • Standard Free Energy Changes
  • Slide 30
  • Fourth Law of Thermodynamics Emergence
  • Slide 32
  • Slide 33
  • Slide 34
  • Slide 35
  • Slide 36
  • Slide 37
  • Slide 38
  • Slide 39
  • Slide 40
  • Slide 41
  • Slide 42
  • Slide 43
  • Slide 44
  • Slide 45
  • Slide 46
  • Slide 47
  • Slide 48
  • Slide 49
  • 2006 (B)
  • Slide 51
  • Slide 52
  • Slide 53
  • Slide 54
  • Slide 55
Page 20: Unit 14: Chemical Thermodynamics

ChemicalThermodynamics

oreactants

oproducts

o298 S S S

Thermodynamic Changes in Systems (Chem Reactions)

Appendix 1 (CHM 1046 Module) notice Sdeg is in J not kJ

Grxn = Gf (products) Gf (reactants)

Hrxn = Hf (products) - Hf (reactants)

ChemicalThermodynamics

Entropy Changes in the Surroundings

bull Heat (q) that flows into or out of the system changes the entropy of the surroundings

Ssurr prop - (qsys)bull For an isothermal process

Ssurr= (qsys)T

bull At constant pressure qsys is simply H for the system

System

q

q

qq

q

q

q

Ssurr= Hsys

TSurroundings

What in a chemical reaction causes entropy changes in the surroundings

ChemicalThermodynamics

Entropy Change in the Universe

K 298

1000 692( kJ) Jxmol kJ

Problem Calculate the Suniv for the synthesis of ammonia 25oC

N2 (g) + 3 H2 (g) 2 NH3 (g) Hdegrxn = - 926 kJmol

Ssurr =-Hsys

T

Ssurr = 311 JKmol

Suniv = Ssyst or rxn + Ssurr

nS(prod) - mS(react)

Sdegsyst = - 199 JKmiddotmol

2(1925) ndash [(1915)+3(1306)]

Suniv = - 1983 JKmiddotmol + 311 JKmol

Suniv = 113 JKmol

ChemicalThermodynamics

Entropy Change in the Universe

bull ThenSuniv = Ssyst + Hsystem

T

Suniv = Ssyst or rxn + Ssurr

Ssurr =-Hsys

Tbull Since

TSuniv = Hsyst TSsyst

TSuniv is defined as the Gibbs (free) Energy G

TSuniv = TSsyst + Hsyst

J Willard Gibbs USA 1839-1903

Multiplying both sides by T

ChemicalThermodynamics

bull When Suniv is positive G is negative

bull When G is negative the process is spontaneous

Gibbs Free Energy (G)

Gibbs Energy (-TΔS) measures the useful or process-initiating work obtainable from an isothermal isobaric thermodynamic system Technically the Gibbs free energy is the maximum amount of non-expansion work which can be extracted from a closed system or this maximum can be attained only in a completely reversible process

Guniv = Hsys TSsysTSuniv =

ChemicalThermodynamics

Free Energy Changes

At temperatures other than 25degC

Gdeg = H TS

How does G change with temperature

bull There are two parts to the free energy equation Hmdash the enthalpy term TS mdash the entropy term

bull The temperature dependence of free energy then comes from the entropy term

ChemicalThermodynamics

Spontaneity Enthalpy amp Entropy

Gdeg = H TS

Spontaneous all T

NonSpontaneous all T

Spontaneous high TSpontaneous low T

ChemicalThermodynamics

Spontaneity Enthalpy amp Entropy

Entropy Driven Reactions

Entropy amp Enthalpy Driven Reaction

Enthalpy Driven Reaction

Na2CO3(s) + HCl(aq) NaCl(aq) + CO2 (g)

2 H2(g) + O2 (g) 2 H2O(g)

NH4NO3(s) NH4+

(aq) + NO3-(aq)

n = 2-3 = -1

S = +H = +

G = H( TS)

EntropySyst+SurrFormationOfWater

(-TS)

(-TS)

(+TS)H = - S = -

H = - S = +

Enthalpy EntropyH2O

ChemicalThermodynamics

ProblemsGdeg = HT(S)

(-763)

ndash (-804)

+41

(3549)

ndash (2219)

+1330

Gdeg = H TS = (1313kJ) T(133kJ)

T = 987

TiCl4(l) TiCl4(g)

(-T)Reactant

Product

ChemicalThermodynamics

Standard Free Energy Changes

Analogous to standard enthalpies of formation are standard free energies of formation G

f

G = nG(products) mGf (reactants)f

where n and m are the stoichiometric coefficients

ChemicalThermodynamics

Standard Free Energy Changes

12 CO2(g) + 6 H2O(g)2 C6H6 (l) + 15 O2 (g)

Grxn = nG(prod) mG(react)f

Calculate the standard free energy changes for the above reaction 25 degC

f

[12(-394) + 6(-229)] ndash [2(125) + 15 (0)]

ndash [2 C6H6 (l) + 15 O2(g)][12 CO2(g) + 6 H2O(g)]

Grxn = - 6352 Jmol K

Standard Molar Gibbs Energy of Formation (Gdegf)

CO2 (g) -394

H2O (g) -229

C6H6 (l) 125

ChemicalThermodynamics

Fourth Law of Thermodynamics EmergenceComplex emergent systems spontaneously (-G) arise when energy flows through a collection of many interacting particles resulting in new patterns of complex behaviors that are much more than the sum of the individual parts (+S)

The formation of these complex patterns in emergent systems is more efficient in the dissipation of energy (-H) thus speeds up the increase of entropy in the universe

G = H -TSA precise definition of emergence and a useful mathematical formulation of this phenomenon remains elusive

C f [n i E(t)]Examples cells forming living organisms stars forming galaxies neurons forming conscious brain

ChemicalThermodynamics

ChemicalThermodynamics

ChemicalThermodynamics

ChemicalThermodynamics

ChemicalThermodynamics

ChemicalThermodynamics

ChemicalThermodynamics

2002 B

ChemicalThermodynamics

ChemicalThermodynamics

ChemicalThermodynamics

2003 A

ChemicalThermodynamics

ChemicalThermodynamics

2004 A

ChemicalThermodynamics

ChemicalThermodynamics

ChemicalThermodynamics

2004 B

ChemicalThermodynamics

ChemicalThermodynamics

2005 A

ChemicalThermodynamics

ChemicalThermodynamics

2006 (B)

ChemicalThermodynamics

ChemicalThermodynamics

ChemicalThermodynamics

2007 (A)

ChemicalThermodynamics

ChemicalThermodynamics

  • Unit 14 Chemical Thermodynamics
  • First Law of Thermodynamics
  • Second Law of Thermodynamics
  • Spontaneous Processes
  • Slide 5
  • Spontaneity
  • Irreversible Processes
  • Entropy (S)
  • Slide 9
  • Second Law of Thermodynamics
  • Slide 11
  • Entropy on the Molecular Scale
  • Slide 13
  • Entropy Changes
  • Third Law of Thermodynamics
  • Standard Entropies
  • Standard Entropies (298 K) from Absolute Entropies (0K)
  • Entropy Changes in the System
  • Slide 19
  • Thermodynamic Changes in Systems (Chem Reactions)
  • Entropy Changes in the Surroundings
  • Entropy Change in the Universe
  • Slide 23
  • Gibbs Free Energy (G)
  • Free Energy Changes
  • Spontaneity Enthalpy amp Entropy
  • Slide 27
  • Problems
  • Standard Free Energy Changes
  • Slide 30
  • Fourth Law of Thermodynamics Emergence
  • Slide 32
  • Slide 33
  • Slide 34
  • Slide 35
  • Slide 36
  • Slide 37
  • Slide 38
  • Slide 39
  • Slide 40
  • Slide 41
  • Slide 42
  • Slide 43
  • Slide 44
  • Slide 45
  • Slide 46
  • Slide 47
  • Slide 48
  • Slide 49
  • 2006 (B)
  • Slide 51
  • Slide 52
  • Slide 53
  • Slide 54
  • Slide 55
Page 21: Unit 14: Chemical Thermodynamics

ChemicalThermodynamics

Entropy Changes in the Surroundings

bull Heat (q) that flows into or out of the system changes the entropy of the surroundings

Ssurr prop - (qsys)bull For an isothermal process

Ssurr= (qsys)T

bull At constant pressure qsys is simply H for the system

System

q

q

qq

q

q

q

Ssurr= Hsys

TSurroundings

What in a chemical reaction causes entropy changes in the surroundings

ChemicalThermodynamics

Entropy Change in the Universe

K 298

1000 692( kJ) Jxmol kJ

Problem Calculate the Suniv for the synthesis of ammonia 25oC

N2 (g) + 3 H2 (g) 2 NH3 (g) Hdegrxn = - 926 kJmol

Ssurr =-Hsys

T

Ssurr = 311 JKmol

Suniv = Ssyst or rxn + Ssurr

nS(prod) - mS(react)

Sdegsyst = - 199 JKmiddotmol

2(1925) ndash [(1915)+3(1306)]

Suniv = - 1983 JKmiddotmol + 311 JKmol

Suniv = 113 JKmol

ChemicalThermodynamics

Entropy Change in the Universe

bull ThenSuniv = Ssyst + Hsystem

T

Suniv = Ssyst or rxn + Ssurr

Ssurr =-Hsys

Tbull Since

TSuniv = Hsyst TSsyst

TSuniv is defined as the Gibbs (free) Energy G

TSuniv = TSsyst + Hsyst

J Willard Gibbs USA 1839-1903

Multiplying both sides by T

ChemicalThermodynamics

bull When Suniv is positive G is negative

bull When G is negative the process is spontaneous

Gibbs Free Energy (G)

Gibbs Energy (-TΔS) measures the useful or process-initiating work obtainable from an isothermal isobaric thermodynamic system Technically the Gibbs free energy is the maximum amount of non-expansion work which can be extracted from a closed system or this maximum can be attained only in a completely reversible process

Guniv = Hsys TSsysTSuniv =

ChemicalThermodynamics

Free Energy Changes

At temperatures other than 25degC

Gdeg = H TS

How does G change with temperature

bull There are two parts to the free energy equation Hmdash the enthalpy term TS mdash the entropy term

bull The temperature dependence of free energy then comes from the entropy term

ChemicalThermodynamics

Spontaneity Enthalpy amp Entropy

Gdeg = H TS

Spontaneous all T

NonSpontaneous all T

Spontaneous high TSpontaneous low T

ChemicalThermodynamics

Spontaneity Enthalpy amp Entropy

Entropy Driven Reactions

Entropy amp Enthalpy Driven Reaction

Enthalpy Driven Reaction

Na2CO3(s) + HCl(aq) NaCl(aq) + CO2 (g)

2 H2(g) + O2 (g) 2 H2O(g)

NH4NO3(s) NH4+

(aq) + NO3-(aq)

n = 2-3 = -1

S = +H = +

G = H( TS)

EntropySyst+SurrFormationOfWater

(-TS)

(-TS)

(+TS)H = - S = -

H = - S = +

Enthalpy EntropyH2O

ChemicalThermodynamics

ProblemsGdeg = HT(S)

(-763)

ndash (-804)

+41

(3549)

ndash (2219)

+1330

Gdeg = H TS = (1313kJ) T(133kJ)

T = 987

TiCl4(l) TiCl4(g)

(-T)Reactant

Product

ChemicalThermodynamics

Standard Free Energy Changes

Analogous to standard enthalpies of formation are standard free energies of formation G

f

G = nG(products) mGf (reactants)f

where n and m are the stoichiometric coefficients

ChemicalThermodynamics

Standard Free Energy Changes

12 CO2(g) + 6 H2O(g)2 C6H6 (l) + 15 O2 (g)

Grxn = nG(prod) mG(react)f

Calculate the standard free energy changes for the above reaction 25 degC

f

[12(-394) + 6(-229)] ndash [2(125) + 15 (0)]

ndash [2 C6H6 (l) + 15 O2(g)][12 CO2(g) + 6 H2O(g)]

Grxn = - 6352 Jmol K

Standard Molar Gibbs Energy of Formation (Gdegf)

CO2 (g) -394

H2O (g) -229

C6H6 (l) 125

ChemicalThermodynamics

Fourth Law of Thermodynamics EmergenceComplex emergent systems spontaneously (-G) arise when energy flows through a collection of many interacting particles resulting in new patterns of complex behaviors that are much more than the sum of the individual parts (+S)

The formation of these complex patterns in emergent systems is more efficient in the dissipation of energy (-H) thus speeds up the increase of entropy in the universe

G = H -TSA precise definition of emergence and a useful mathematical formulation of this phenomenon remains elusive

C f [n i E(t)]Examples cells forming living organisms stars forming galaxies neurons forming conscious brain

ChemicalThermodynamics

ChemicalThermodynamics

ChemicalThermodynamics

ChemicalThermodynamics

ChemicalThermodynamics

ChemicalThermodynamics

ChemicalThermodynamics

2002 B

ChemicalThermodynamics

ChemicalThermodynamics

ChemicalThermodynamics

2003 A

ChemicalThermodynamics

ChemicalThermodynamics

2004 A

ChemicalThermodynamics

ChemicalThermodynamics

ChemicalThermodynamics

2004 B

ChemicalThermodynamics

ChemicalThermodynamics

2005 A

ChemicalThermodynamics

ChemicalThermodynamics

2006 (B)

ChemicalThermodynamics

ChemicalThermodynamics

ChemicalThermodynamics

2007 (A)

ChemicalThermodynamics

ChemicalThermodynamics

  • Unit 14 Chemical Thermodynamics
  • First Law of Thermodynamics
  • Second Law of Thermodynamics
  • Spontaneous Processes
  • Slide 5
  • Spontaneity
  • Irreversible Processes
  • Entropy (S)
  • Slide 9
  • Second Law of Thermodynamics
  • Slide 11
  • Entropy on the Molecular Scale
  • Slide 13
  • Entropy Changes
  • Third Law of Thermodynamics
  • Standard Entropies
  • Standard Entropies (298 K) from Absolute Entropies (0K)
  • Entropy Changes in the System
  • Slide 19
  • Thermodynamic Changes in Systems (Chem Reactions)
  • Entropy Changes in the Surroundings
  • Entropy Change in the Universe
  • Slide 23
  • Gibbs Free Energy (G)
  • Free Energy Changes
  • Spontaneity Enthalpy amp Entropy
  • Slide 27
  • Problems
  • Standard Free Energy Changes
  • Slide 30
  • Fourth Law of Thermodynamics Emergence
  • Slide 32
  • Slide 33
  • Slide 34
  • Slide 35
  • Slide 36
  • Slide 37
  • Slide 38
  • Slide 39
  • Slide 40
  • Slide 41
  • Slide 42
  • Slide 43
  • Slide 44
  • Slide 45
  • Slide 46
  • Slide 47
  • Slide 48
  • Slide 49
  • 2006 (B)
  • Slide 51
  • Slide 52
  • Slide 53
  • Slide 54
  • Slide 55
Page 22: Unit 14: Chemical Thermodynamics

ChemicalThermodynamics

Entropy Change in the Universe

K 298

1000 692( kJ) Jxmol kJ

Problem Calculate the Suniv for the synthesis of ammonia 25oC

N2 (g) + 3 H2 (g) 2 NH3 (g) Hdegrxn = - 926 kJmol

Ssurr =-Hsys

T

Ssurr = 311 JKmol

Suniv = Ssyst or rxn + Ssurr

nS(prod) - mS(react)

Sdegsyst = - 199 JKmiddotmol

2(1925) ndash [(1915)+3(1306)]

Suniv = - 1983 JKmiddotmol + 311 JKmol

Suniv = 113 JKmol

ChemicalThermodynamics

Entropy Change in the Universe

bull ThenSuniv = Ssyst + Hsystem

T

Suniv = Ssyst or rxn + Ssurr

Ssurr =-Hsys

Tbull Since

TSuniv = Hsyst TSsyst

TSuniv is defined as the Gibbs (free) Energy G

TSuniv = TSsyst + Hsyst

J Willard Gibbs USA 1839-1903

Multiplying both sides by T

ChemicalThermodynamics

bull When Suniv is positive G is negative

bull When G is negative the process is spontaneous

Gibbs Free Energy (G)

Gibbs Energy (-TΔS) measures the useful or process-initiating work obtainable from an isothermal isobaric thermodynamic system Technically the Gibbs free energy is the maximum amount of non-expansion work which can be extracted from a closed system or this maximum can be attained only in a completely reversible process

Guniv = Hsys TSsysTSuniv =

ChemicalThermodynamics

Free Energy Changes

At temperatures other than 25degC

Gdeg = H TS

How does G change with temperature

bull There are two parts to the free energy equation Hmdash the enthalpy term TS mdash the entropy term

bull The temperature dependence of free energy then comes from the entropy term

ChemicalThermodynamics

Spontaneity Enthalpy amp Entropy

Gdeg = H TS

Spontaneous all T

NonSpontaneous all T

Spontaneous high TSpontaneous low T

ChemicalThermodynamics

Spontaneity Enthalpy amp Entropy

Entropy Driven Reactions

Entropy amp Enthalpy Driven Reaction

Enthalpy Driven Reaction

Na2CO3(s) + HCl(aq) NaCl(aq) + CO2 (g)

2 H2(g) + O2 (g) 2 H2O(g)

NH4NO3(s) NH4+

(aq) + NO3-(aq)

n = 2-3 = -1

S = +H = +

G = H( TS)

EntropySyst+SurrFormationOfWater

(-TS)

(-TS)

(+TS)H = - S = -

H = - S = +

Enthalpy EntropyH2O

ChemicalThermodynamics

ProblemsGdeg = HT(S)

(-763)

ndash (-804)

+41

(3549)

ndash (2219)

+1330

Gdeg = H TS = (1313kJ) T(133kJ)

T = 987

TiCl4(l) TiCl4(g)

(-T)Reactant

Product

ChemicalThermodynamics

Standard Free Energy Changes

Analogous to standard enthalpies of formation are standard free energies of formation G

f

G = nG(products) mGf (reactants)f

where n and m are the stoichiometric coefficients

ChemicalThermodynamics

Standard Free Energy Changes

12 CO2(g) + 6 H2O(g)2 C6H6 (l) + 15 O2 (g)

Grxn = nG(prod) mG(react)f

Calculate the standard free energy changes for the above reaction 25 degC

f

[12(-394) + 6(-229)] ndash [2(125) + 15 (0)]

ndash [2 C6H6 (l) + 15 O2(g)][12 CO2(g) + 6 H2O(g)]

Grxn = - 6352 Jmol K

Standard Molar Gibbs Energy of Formation (Gdegf)

CO2 (g) -394

H2O (g) -229

C6H6 (l) 125

ChemicalThermodynamics

Fourth Law of Thermodynamics EmergenceComplex emergent systems spontaneously (-G) arise when energy flows through a collection of many interacting particles resulting in new patterns of complex behaviors that are much more than the sum of the individual parts (+S)

The formation of these complex patterns in emergent systems is more efficient in the dissipation of energy (-H) thus speeds up the increase of entropy in the universe

G = H -TSA precise definition of emergence and a useful mathematical formulation of this phenomenon remains elusive

C f [n i E(t)]Examples cells forming living organisms stars forming galaxies neurons forming conscious brain

ChemicalThermodynamics

ChemicalThermodynamics

ChemicalThermodynamics

ChemicalThermodynamics

ChemicalThermodynamics

ChemicalThermodynamics

ChemicalThermodynamics

2002 B

ChemicalThermodynamics

ChemicalThermodynamics

ChemicalThermodynamics

2003 A

ChemicalThermodynamics

ChemicalThermodynamics

2004 A

ChemicalThermodynamics

ChemicalThermodynamics

ChemicalThermodynamics

2004 B

ChemicalThermodynamics

ChemicalThermodynamics

2005 A

ChemicalThermodynamics

ChemicalThermodynamics

2006 (B)

ChemicalThermodynamics

ChemicalThermodynamics

ChemicalThermodynamics

2007 (A)

ChemicalThermodynamics

ChemicalThermodynamics

  • Unit 14 Chemical Thermodynamics
  • First Law of Thermodynamics
  • Second Law of Thermodynamics
  • Spontaneous Processes
  • Slide 5
  • Spontaneity
  • Irreversible Processes
  • Entropy (S)
  • Slide 9
  • Second Law of Thermodynamics
  • Slide 11
  • Entropy on the Molecular Scale
  • Slide 13
  • Entropy Changes
  • Third Law of Thermodynamics
  • Standard Entropies
  • Standard Entropies (298 K) from Absolute Entropies (0K)
  • Entropy Changes in the System
  • Slide 19
  • Thermodynamic Changes in Systems (Chem Reactions)
  • Entropy Changes in the Surroundings
  • Entropy Change in the Universe
  • Slide 23
  • Gibbs Free Energy (G)
  • Free Energy Changes
  • Spontaneity Enthalpy amp Entropy
  • Slide 27
  • Problems
  • Standard Free Energy Changes
  • Slide 30
  • Fourth Law of Thermodynamics Emergence
  • Slide 32
  • Slide 33
  • Slide 34
  • Slide 35
  • Slide 36
  • Slide 37
  • Slide 38
  • Slide 39
  • Slide 40
  • Slide 41
  • Slide 42
  • Slide 43
  • Slide 44
  • Slide 45
  • Slide 46
  • Slide 47
  • Slide 48
  • Slide 49
  • 2006 (B)
  • Slide 51
  • Slide 52
  • Slide 53
  • Slide 54
  • Slide 55
Page 23: Unit 14: Chemical Thermodynamics

ChemicalThermodynamics

Entropy Change in the Universe

bull ThenSuniv = Ssyst + Hsystem

T

Suniv = Ssyst or rxn + Ssurr

Ssurr =-Hsys

Tbull Since

TSuniv = Hsyst TSsyst

TSuniv is defined as the Gibbs (free) Energy G

TSuniv = TSsyst + Hsyst

J Willard Gibbs USA 1839-1903

Multiplying both sides by T

ChemicalThermodynamics

bull When Suniv is positive G is negative

bull When G is negative the process is spontaneous

Gibbs Free Energy (G)

Gibbs Energy (-TΔS) measures the useful or process-initiating work obtainable from an isothermal isobaric thermodynamic system Technically the Gibbs free energy is the maximum amount of non-expansion work which can be extracted from a closed system or this maximum can be attained only in a completely reversible process

Guniv = Hsys TSsysTSuniv =

ChemicalThermodynamics

Free Energy Changes

At temperatures other than 25degC

Gdeg = H TS

How does G change with temperature

bull There are two parts to the free energy equation Hmdash the enthalpy term TS mdash the entropy term

bull The temperature dependence of free energy then comes from the entropy term

ChemicalThermodynamics

Spontaneity Enthalpy amp Entropy

Gdeg = H TS

Spontaneous all T

NonSpontaneous all T

Spontaneous high TSpontaneous low T

ChemicalThermodynamics

Spontaneity Enthalpy amp Entropy

Entropy Driven Reactions

Entropy amp Enthalpy Driven Reaction

Enthalpy Driven Reaction

Na2CO3(s) + HCl(aq) NaCl(aq) + CO2 (g)

2 H2(g) + O2 (g) 2 H2O(g)

NH4NO3(s) NH4+

(aq) + NO3-(aq)

n = 2-3 = -1

S = +H = +

G = H( TS)

EntropySyst+SurrFormationOfWater

(-TS)

(-TS)

(+TS)H = - S = -

H = - S = +

Enthalpy EntropyH2O

ChemicalThermodynamics

ProblemsGdeg = HT(S)

(-763)

ndash (-804)

+41

(3549)

ndash (2219)

+1330

Gdeg = H TS = (1313kJ) T(133kJ)

T = 987

TiCl4(l) TiCl4(g)

(-T)Reactant

Product

ChemicalThermodynamics

Standard Free Energy Changes

Analogous to standard enthalpies of formation are standard free energies of formation G

f

G = nG(products) mGf (reactants)f

where n and m are the stoichiometric coefficients

ChemicalThermodynamics

Standard Free Energy Changes

12 CO2(g) + 6 H2O(g)2 C6H6 (l) + 15 O2 (g)

Grxn = nG(prod) mG(react)f

Calculate the standard free energy changes for the above reaction 25 degC

f

[12(-394) + 6(-229)] ndash [2(125) + 15 (0)]

ndash [2 C6H6 (l) + 15 O2(g)][12 CO2(g) + 6 H2O(g)]

Grxn = - 6352 Jmol K

Standard Molar Gibbs Energy of Formation (Gdegf)

CO2 (g) -394

H2O (g) -229

C6H6 (l) 125

ChemicalThermodynamics

Fourth Law of Thermodynamics EmergenceComplex emergent systems spontaneously (-G) arise when energy flows through a collection of many interacting particles resulting in new patterns of complex behaviors that are much more than the sum of the individual parts (+S)

The formation of these complex patterns in emergent systems is more efficient in the dissipation of energy (-H) thus speeds up the increase of entropy in the universe

G = H -TSA precise definition of emergence and a useful mathematical formulation of this phenomenon remains elusive

C f [n i E(t)]Examples cells forming living organisms stars forming galaxies neurons forming conscious brain

ChemicalThermodynamics

ChemicalThermodynamics

ChemicalThermodynamics

ChemicalThermodynamics

ChemicalThermodynamics

ChemicalThermodynamics

ChemicalThermodynamics

2002 B

ChemicalThermodynamics

ChemicalThermodynamics

ChemicalThermodynamics

2003 A

ChemicalThermodynamics

ChemicalThermodynamics

2004 A

ChemicalThermodynamics

ChemicalThermodynamics

ChemicalThermodynamics

2004 B

ChemicalThermodynamics

ChemicalThermodynamics

2005 A

ChemicalThermodynamics

ChemicalThermodynamics

2006 (B)

ChemicalThermodynamics

ChemicalThermodynamics

ChemicalThermodynamics

2007 (A)

ChemicalThermodynamics

ChemicalThermodynamics

  • Unit 14 Chemical Thermodynamics
  • First Law of Thermodynamics
  • Second Law of Thermodynamics
  • Spontaneous Processes
  • Slide 5
  • Spontaneity
  • Irreversible Processes
  • Entropy (S)
  • Slide 9
  • Second Law of Thermodynamics
  • Slide 11
  • Entropy on the Molecular Scale
  • Slide 13
  • Entropy Changes
  • Third Law of Thermodynamics
  • Standard Entropies
  • Standard Entropies (298 K) from Absolute Entropies (0K)
  • Entropy Changes in the System
  • Slide 19
  • Thermodynamic Changes in Systems (Chem Reactions)
  • Entropy Changes in the Surroundings
  • Entropy Change in the Universe
  • Slide 23
  • Gibbs Free Energy (G)
  • Free Energy Changes
  • Spontaneity Enthalpy amp Entropy
  • Slide 27
  • Problems
  • Standard Free Energy Changes
  • Slide 30
  • Fourth Law of Thermodynamics Emergence
  • Slide 32
  • Slide 33
  • Slide 34
  • Slide 35
  • Slide 36
  • Slide 37
  • Slide 38
  • Slide 39
  • Slide 40
  • Slide 41
  • Slide 42
  • Slide 43
  • Slide 44
  • Slide 45
  • Slide 46
  • Slide 47
  • Slide 48
  • Slide 49
  • 2006 (B)
  • Slide 51
  • Slide 52
  • Slide 53
  • Slide 54
  • Slide 55
Page 24: Unit 14: Chemical Thermodynamics

ChemicalThermodynamics

bull When Suniv is positive G is negative

bull When G is negative the process is spontaneous

Gibbs Free Energy (G)

Gibbs Energy (-TΔS) measures the useful or process-initiating work obtainable from an isothermal isobaric thermodynamic system Technically the Gibbs free energy is the maximum amount of non-expansion work which can be extracted from a closed system or this maximum can be attained only in a completely reversible process

Guniv = Hsys TSsysTSuniv =

ChemicalThermodynamics

Free Energy Changes

At temperatures other than 25degC

Gdeg = H TS

How does G change with temperature

bull There are two parts to the free energy equation Hmdash the enthalpy term TS mdash the entropy term

bull The temperature dependence of free energy then comes from the entropy term

ChemicalThermodynamics

Spontaneity Enthalpy amp Entropy

Gdeg = H TS

Spontaneous all T

NonSpontaneous all T

Spontaneous high TSpontaneous low T

ChemicalThermodynamics

Spontaneity Enthalpy amp Entropy

Entropy Driven Reactions

Entropy amp Enthalpy Driven Reaction

Enthalpy Driven Reaction

Na2CO3(s) + HCl(aq) NaCl(aq) + CO2 (g)

2 H2(g) + O2 (g) 2 H2O(g)

NH4NO3(s) NH4+

(aq) + NO3-(aq)

n = 2-3 = -1

S = +H = +

G = H( TS)

EntropySyst+SurrFormationOfWater

(-TS)

(-TS)

(+TS)H = - S = -

H = - S = +

Enthalpy EntropyH2O

ChemicalThermodynamics

ProblemsGdeg = HT(S)

(-763)

ndash (-804)

+41

(3549)

ndash (2219)

+1330

Gdeg = H TS = (1313kJ) T(133kJ)

T = 987

TiCl4(l) TiCl4(g)

(-T)Reactant

Product

ChemicalThermodynamics

Standard Free Energy Changes

Analogous to standard enthalpies of formation are standard free energies of formation G

f

G = nG(products) mGf (reactants)f

where n and m are the stoichiometric coefficients

ChemicalThermodynamics

Standard Free Energy Changes

12 CO2(g) + 6 H2O(g)2 C6H6 (l) + 15 O2 (g)

Grxn = nG(prod) mG(react)f

Calculate the standard free energy changes for the above reaction 25 degC

f

[12(-394) + 6(-229)] ndash [2(125) + 15 (0)]

ndash [2 C6H6 (l) + 15 O2(g)][12 CO2(g) + 6 H2O(g)]

Grxn = - 6352 Jmol K

Standard Molar Gibbs Energy of Formation (Gdegf)

CO2 (g) -394

H2O (g) -229

C6H6 (l) 125

ChemicalThermodynamics

Fourth Law of Thermodynamics EmergenceComplex emergent systems spontaneously (-G) arise when energy flows through a collection of many interacting particles resulting in new patterns of complex behaviors that are much more than the sum of the individual parts (+S)

The formation of these complex patterns in emergent systems is more efficient in the dissipation of energy (-H) thus speeds up the increase of entropy in the universe

G = H -TSA precise definition of emergence and a useful mathematical formulation of this phenomenon remains elusive

C f [n i E(t)]Examples cells forming living organisms stars forming galaxies neurons forming conscious brain

ChemicalThermodynamics

ChemicalThermodynamics

ChemicalThermodynamics

ChemicalThermodynamics

ChemicalThermodynamics

ChemicalThermodynamics

ChemicalThermodynamics

2002 B

ChemicalThermodynamics

ChemicalThermodynamics

ChemicalThermodynamics

2003 A

ChemicalThermodynamics

ChemicalThermodynamics

2004 A

ChemicalThermodynamics

ChemicalThermodynamics

ChemicalThermodynamics

2004 B

ChemicalThermodynamics

ChemicalThermodynamics

2005 A

ChemicalThermodynamics

ChemicalThermodynamics

2006 (B)

ChemicalThermodynamics

ChemicalThermodynamics

ChemicalThermodynamics

2007 (A)

ChemicalThermodynamics

ChemicalThermodynamics

  • Unit 14 Chemical Thermodynamics
  • First Law of Thermodynamics
  • Second Law of Thermodynamics
  • Spontaneous Processes
  • Slide 5
  • Spontaneity
  • Irreversible Processes
  • Entropy (S)
  • Slide 9
  • Second Law of Thermodynamics
  • Slide 11
  • Entropy on the Molecular Scale
  • Slide 13
  • Entropy Changes
  • Third Law of Thermodynamics
  • Standard Entropies
  • Standard Entropies (298 K) from Absolute Entropies (0K)
  • Entropy Changes in the System
  • Slide 19
  • Thermodynamic Changes in Systems (Chem Reactions)
  • Entropy Changes in the Surroundings
  • Entropy Change in the Universe
  • Slide 23
  • Gibbs Free Energy (G)
  • Free Energy Changes
  • Spontaneity Enthalpy amp Entropy
  • Slide 27
  • Problems
  • Standard Free Energy Changes
  • Slide 30
  • Fourth Law of Thermodynamics Emergence
  • Slide 32
  • Slide 33
  • Slide 34
  • Slide 35
  • Slide 36
  • Slide 37
  • Slide 38
  • Slide 39
  • Slide 40
  • Slide 41
  • Slide 42
  • Slide 43
  • Slide 44
  • Slide 45
  • Slide 46
  • Slide 47
  • Slide 48
  • Slide 49
  • 2006 (B)
  • Slide 51
  • Slide 52
  • Slide 53
  • Slide 54
  • Slide 55
Page 25: Unit 14: Chemical Thermodynamics

ChemicalThermodynamics

Free Energy Changes

At temperatures other than 25degC

Gdeg = H TS

How does G change with temperature

bull There are two parts to the free energy equation Hmdash the enthalpy term TS mdash the entropy term

bull The temperature dependence of free energy then comes from the entropy term

ChemicalThermodynamics

Spontaneity Enthalpy amp Entropy

Gdeg = H TS

Spontaneous all T

NonSpontaneous all T

Spontaneous high TSpontaneous low T

ChemicalThermodynamics

Spontaneity Enthalpy amp Entropy

Entropy Driven Reactions

Entropy amp Enthalpy Driven Reaction

Enthalpy Driven Reaction

Na2CO3(s) + HCl(aq) NaCl(aq) + CO2 (g)

2 H2(g) + O2 (g) 2 H2O(g)

NH4NO3(s) NH4+

(aq) + NO3-(aq)

n = 2-3 = -1

S = +H = +

G = H( TS)

EntropySyst+SurrFormationOfWater

(-TS)

(-TS)

(+TS)H = - S = -

H = - S = +

Enthalpy EntropyH2O

ChemicalThermodynamics

ProblemsGdeg = HT(S)

(-763)

ndash (-804)

+41

(3549)

ndash (2219)

+1330

Gdeg = H TS = (1313kJ) T(133kJ)

T = 987

TiCl4(l) TiCl4(g)

(-T)Reactant

Product

ChemicalThermodynamics

Standard Free Energy Changes

Analogous to standard enthalpies of formation are standard free energies of formation G

f

G = nG(products) mGf (reactants)f

where n and m are the stoichiometric coefficients

ChemicalThermodynamics

Standard Free Energy Changes

12 CO2(g) + 6 H2O(g)2 C6H6 (l) + 15 O2 (g)

Grxn = nG(prod) mG(react)f

Calculate the standard free energy changes for the above reaction 25 degC

f

[12(-394) + 6(-229)] ndash [2(125) + 15 (0)]

ndash [2 C6H6 (l) + 15 O2(g)][12 CO2(g) + 6 H2O(g)]

Grxn = - 6352 Jmol K

Standard Molar Gibbs Energy of Formation (Gdegf)

CO2 (g) -394

H2O (g) -229

C6H6 (l) 125

ChemicalThermodynamics

Fourth Law of Thermodynamics EmergenceComplex emergent systems spontaneously (-G) arise when energy flows through a collection of many interacting particles resulting in new patterns of complex behaviors that are much more than the sum of the individual parts (+S)

The formation of these complex patterns in emergent systems is more efficient in the dissipation of energy (-H) thus speeds up the increase of entropy in the universe

G = H -TSA precise definition of emergence and a useful mathematical formulation of this phenomenon remains elusive

C f [n i E(t)]Examples cells forming living organisms stars forming galaxies neurons forming conscious brain

ChemicalThermodynamics

ChemicalThermodynamics

ChemicalThermodynamics

ChemicalThermodynamics

ChemicalThermodynamics

ChemicalThermodynamics

ChemicalThermodynamics

2002 B

ChemicalThermodynamics

ChemicalThermodynamics

ChemicalThermodynamics

2003 A

ChemicalThermodynamics

ChemicalThermodynamics

2004 A

ChemicalThermodynamics

ChemicalThermodynamics

ChemicalThermodynamics

2004 B

ChemicalThermodynamics

ChemicalThermodynamics

2005 A

ChemicalThermodynamics

ChemicalThermodynamics

2006 (B)

ChemicalThermodynamics

ChemicalThermodynamics

ChemicalThermodynamics

2007 (A)

ChemicalThermodynamics

ChemicalThermodynamics

  • Unit 14 Chemical Thermodynamics
  • First Law of Thermodynamics
  • Second Law of Thermodynamics
  • Spontaneous Processes
  • Slide 5
  • Spontaneity
  • Irreversible Processes
  • Entropy (S)
  • Slide 9
  • Second Law of Thermodynamics
  • Slide 11
  • Entropy on the Molecular Scale
  • Slide 13
  • Entropy Changes
  • Third Law of Thermodynamics
  • Standard Entropies
  • Standard Entropies (298 K) from Absolute Entropies (0K)
  • Entropy Changes in the System
  • Slide 19
  • Thermodynamic Changes in Systems (Chem Reactions)
  • Entropy Changes in the Surroundings
  • Entropy Change in the Universe
  • Slide 23
  • Gibbs Free Energy (G)
  • Free Energy Changes
  • Spontaneity Enthalpy amp Entropy
  • Slide 27
  • Problems
  • Standard Free Energy Changes
  • Slide 30
  • Fourth Law of Thermodynamics Emergence
  • Slide 32
  • Slide 33
  • Slide 34
  • Slide 35
  • Slide 36
  • Slide 37
  • Slide 38
  • Slide 39
  • Slide 40
  • Slide 41
  • Slide 42
  • Slide 43
  • Slide 44
  • Slide 45
  • Slide 46
  • Slide 47
  • Slide 48
  • Slide 49
  • 2006 (B)
  • Slide 51
  • Slide 52
  • Slide 53
  • Slide 54
  • Slide 55
Page 26: Unit 14: Chemical Thermodynamics

ChemicalThermodynamics

Spontaneity Enthalpy amp Entropy

Gdeg = H TS

Spontaneous all T

NonSpontaneous all T

Spontaneous high TSpontaneous low T

ChemicalThermodynamics

Spontaneity Enthalpy amp Entropy

Entropy Driven Reactions

Entropy amp Enthalpy Driven Reaction

Enthalpy Driven Reaction

Na2CO3(s) + HCl(aq) NaCl(aq) + CO2 (g)

2 H2(g) + O2 (g) 2 H2O(g)

NH4NO3(s) NH4+

(aq) + NO3-(aq)

n = 2-3 = -1

S = +H = +

G = H( TS)

EntropySyst+SurrFormationOfWater

(-TS)

(-TS)

(+TS)H = - S = -

H = - S = +

Enthalpy EntropyH2O

ChemicalThermodynamics

ProblemsGdeg = HT(S)

(-763)

ndash (-804)

+41

(3549)

ndash (2219)

+1330

Gdeg = H TS = (1313kJ) T(133kJ)

T = 987

TiCl4(l) TiCl4(g)

(-T)Reactant

Product

ChemicalThermodynamics

Standard Free Energy Changes

Analogous to standard enthalpies of formation are standard free energies of formation G

f

G = nG(products) mGf (reactants)f

where n and m are the stoichiometric coefficients

ChemicalThermodynamics

Standard Free Energy Changes

12 CO2(g) + 6 H2O(g)2 C6H6 (l) + 15 O2 (g)

Grxn = nG(prod) mG(react)f

Calculate the standard free energy changes for the above reaction 25 degC

f

[12(-394) + 6(-229)] ndash [2(125) + 15 (0)]

ndash [2 C6H6 (l) + 15 O2(g)][12 CO2(g) + 6 H2O(g)]

Grxn = - 6352 Jmol K

Standard Molar Gibbs Energy of Formation (Gdegf)

CO2 (g) -394

H2O (g) -229

C6H6 (l) 125

ChemicalThermodynamics

Fourth Law of Thermodynamics EmergenceComplex emergent systems spontaneously (-G) arise when energy flows through a collection of many interacting particles resulting in new patterns of complex behaviors that are much more than the sum of the individual parts (+S)

The formation of these complex patterns in emergent systems is more efficient in the dissipation of energy (-H) thus speeds up the increase of entropy in the universe

G = H -TSA precise definition of emergence and a useful mathematical formulation of this phenomenon remains elusive

C f [n i E(t)]Examples cells forming living organisms stars forming galaxies neurons forming conscious brain

ChemicalThermodynamics

ChemicalThermodynamics

ChemicalThermodynamics

ChemicalThermodynamics

ChemicalThermodynamics

ChemicalThermodynamics

ChemicalThermodynamics

2002 B

ChemicalThermodynamics

ChemicalThermodynamics

ChemicalThermodynamics

2003 A

ChemicalThermodynamics

ChemicalThermodynamics

2004 A

ChemicalThermodynamics

ChemicalThermodynamics

ChemicalThermodynamics

2004 B

ChemicalThermodynamics

ChemicalThermodynamics

2005 A

ChemicalThermodynamics

ChemicalThermodynamics

2006 (B)

ChemicalThermodynamics

ChemicalThermodynamics

ChemicalThermodynamics

2007 (A)

ChemicalThermodynamics

ChemicalThermodynamics

  • Unit 14 Chemical Thermodynamics
  • First Law of Thermodynamics
  • Second Law of Thermodynamics
  • Spontaneous Processes
  • Slide 5
  • Spontaneity
  • Irreversible Processes
  • Entropy (S)
  • Slide 9
  • Second Law of Thermodynamics
  • Slide 11
  • Entropy on the Molecular Scale
  • Slide 13
  • Entropy Changes
  • Third Law of Thermodynamics
  • Standard Entropies
  • Standard Entropies (298 K) from Absolute Entropies (0K)
  • Entropy Changes in the System
  • Slide 19
  • Thermodynamic Changes in Systems (Chem Reactions)
  • Entropy Changes in the Surroundings
  • Entropy Change in the Universe
  • Slide 23
  • Gibbs Free Energy (G)
  • Free Energy Changes
  • Spontaneity Enthalpy amp Entropy
  • Slide 27
  • Problems
  • Standard Free Energy Changes
  • Slide 30
  • Fourth Law of Thermodynamics Emergence
  • Slide 32
  • Slide 33
  • Slide 34
  • Slide 35
  • Slide 36
  • Slide 37
  • Slide 38
  • Slide 39
  • Slide 40
  • Slide 41
  • Slide 42
  • Slide 43
  • Slide 44
  • Slide 45
  • Slide 46
  • Slide 47
  • Slide 48
  • Slide 49
  • 2006 (B)
  • Slide 51
  • Slide 52
  • Slide 53
  • Slide 54
  • Slide 55
Page 27: Unit 14: Chemical Thermodynamics

ChemicalThermodynamics

Spontaneity Enthalpy amp Entropy

Entropy Driven Reactions

Entropy amp Enthalpy Driven Reaction

Enthalpy Driven Reaction

Na2CO3(s) + HCl(aq) NaCl(aq) + CO2 (g)

2 H2(g) + O2 (g) 2 H2O(g)

NH4NO3(s) NH4+

(aq) + NO3-(aq)

n = 2-3 = -1

S = +H = +

G = H( TS)

EntropySyst+SurrFormationOfWater

(-TS)

(-TS)

(+TS)H = - S = -

H = - S = +

Enthalpy EntropyH2O

ChemicalThermodynamics

ProblemsGdeg = HT(S)

(-763)

ndash (-804)

+41

(3549)

ndash (2219)

+1330

Gdeg = H TS = (1313kJ) T(133kJ)

T = 987

TiCl4(l) TiCl4(g)

(-T)Reactant

Product

ChemicalThermodynamics

Standard Free Energy Changes

Analogous to standard enthalpies of formation are standard free energies of formation G

f

G = nG(products) mGf (reactants)f

where n and m are the stoichiometric coefficients

ChemicalThermodynamics

Standard Free Energy Changes

12 CO2(g) + 6 H2O(g)2 C6H6 (l) + 15 O2 (g)

Grxn = nG(prod) mG(react)f

Calculate the standard free energy changes for the above reaction 25 degC

f

[12(-394) + 6(-229)] ndash [2(125) + 15 (0)]

ndash [2 C6H6 (l) + 15 O2(g)][12 CO2(g) + 6 H2O(g)]

Grxn = - 6352 Jmol K

Standard Molar Gibbs Energy of Formation (Gdegf)

CO2 (g) -394

H2O (g) -229

C6H6 (l) 125

ChemicalThermodynamics

Fourth Law of Thermodynamics EmergenceComplex emergent systems spontaneously (-G) arise when energy flows through a collection of many interacting particles resulting in new patterns of complex behaviors that are much more than the sum of the individual parts (+S)

The formation of these complex patterns in emergent systems is more efficient in the dissipation of energy (-H) thus speeds up the increase of entropy in the universe

G = H -TSA precise definition of emergence and a useful mathematical formulation of this phenomenon remains elusive

C f [n i E(t)]Examples cells forming living organisms stars forming galaxies neurons forming conscious brain

ChemicalThermodynamics

ChemicalThermodynamics

ChemicalThermodynamics

ChemicalThermodynamics

ChemicalThermodynamics

ChemicalThermodynamics

ChemicalThermodynamics

2002 B

ChemicalThermodynamics

ChemicalThermodynamics

ChemicalThermodynamics

2003 A

ChemicalThermodynamics

ChemicalThermodynamics

2004 A

ChemicalThermodynamics

ChemicalThermodynamics

ChemicalThermodynamics

2004 B

ChemicalThermodynamics

ChemicalThermodynamics

2005 A

ChemicalThermodynamics

ChemicalThermodynamics

2006 (B)

ChemicalThermodynamics

ChemicalThermodynamics

ChemicalThermodynamics

2007 (A)

ChemicalThermodynamics

ChemicalThermodynamics

  • Unit 14 Chemical Thermodynamics
  • First Law of Thermodynamics
  • Second Law of Thermodynamics
  • Spontaneous Processes
  • Slide 5
  • Spontaneity
  • Irreversible Processes
  • Entropy (S)
  • Slide 9
  • Second Law of Thermodynamics
  • Slide 11
  • Entropy on the Molecular Scale
  • Slide 13
  • Entropy Changes
  • Third Law of Thermodynamics
  • Standard Entropies
  • Standard Entropies (298 K) from Absolute Entropies (0K)
  • Entropy Changes in the System
  • Slide 19
  • Thermodynamic Changes in Systems (Chem Reactions)
  • Entropy Changes in the Surroundings
  • Entropy Change in the Universe
  • Slide 23
  • Gibbs Free Energy (G)
  • Free Energy Changes
  • Spontaneity Enthalpy amp Entropy
  • Slide 27
  • Problems
  • Standard Free Energy Changes
  • Slide 30
  • Fourth Law of Thermodynamics Emergence
  • Slide 32
  • Slide 33
  • Slide 34
  • Slide 35
  • Slide 36
  • Slide 37
  • Slide 38
  • Slide 39
  • Slide 40
  • Slide 41
  • Slide 42
  • Slide 43
  • Slide 44
  • Slide 45
  • Slide 46
  • Slide 47
  • Slide 48
  • Slide 49
  • 2006 (B)
  • Slide 51
  • Slide 52
  • Slide 53
  • Slide 54
  • Slide 55
Page 28: Unit 14: Chemical Thermodynamics

ChemicalThermodynamics

ProblemsGdeg = HT(S)

(-763)

ndash (-804)

+41

(3549)

ndash (2219)

+1330

Gdeg = H TS = (1313kJ) T(133kJ)

T = 987

TiCl4(l) TiCl4(g)

(-T)Reactant

Product

ChemicalThermodynamics

Standard Free Energy Changes

Analogous to standard enthalpies of formation are standard free energies of formation G

f

G = nG(products) mGf (reactants)f

where n and m are the stoichiometric coefficients

ChemicalThermodynamics

Standard Free Energy Changes

12 CO2(g) + 6 H2O(g)2 C6H6 (l) + 15 O2 (g)

Grxn = nG(prod) mG(react)f

Calculate the standard free energy changes for the above reaction 25 degC

f

[12(-394) + 6(-229)] ndash [2(125) + 15 (0)]

ndash [2 C6H6 (l) + 15 O2(g)][12 CO2(g) + 6 H2O(g)]

Grxn = - 6352 Jmol K

Standard Molar Gibbs Energy of Formation (Gdegf)

CO2 (g) -394

H2O (g) -229

C6H6 (l) 125

ChemicalThermodynamics

Fourth Law of Thermodynamics EmergenceComplex emergent systems spontaneously (-G) arise when energy flows through a collection of many interacting particles resulting in new patterns of complex behaviors that are much more than the sum of the individual parts (+S)

The formation of these complex patterns in emergent systems is more efficient in the dissipation of energy (-H) thus speeds up the increase of entropy in the universe

G = H -TSA precise definition of emergence and a useful mathematical formulation of this phenomenon remains elusive

C f [n i E(t)]Examples cells forming living organisms stars forming galaxies neurons forming conscious brain

ChemicalThermodynamics

ChemicalThermodynamics

ChemicalThermodynamics

ChemicalThermodynamics

ChemicalThermodynamics

ChemicalThermodynamics

ChemicalThermodynamics

2002 B

ChemicalThermodynamics

ChemicalThermodynamics

ChemicalThermodynamics

2003 A

ChemicalThermodynamics

ChemicalThermodynamics

2004 A

ChemicalThermodynamics

ChemicalThermodynamics

ChemicalThermodynamics

2004 B

ChemicalThermodynamics

ChemicalThermodynamics

2005 A

ChemicalThermodynamics

ChemicalThermodynamics

2006 (B)

ChemicalThermodynamics

ChemicalThermodynamics

ChemicalThermodynamics

2007 (A)

ChemicalThermodynamics

ChemicalThermodynamics

  • Unit 14 Chemical Thermodynamics
  • First Law of Thermodynamics
  • Second Law of Thermodynamics
  • Spontaneous Processes
  • Slide 5
  • Spontaneity
  • Irreversible Processes
  • Entropy (S)
  • Slide 9
  • Second Law of Thermodynamics
  • Slide 11
  • Entropy on the Molecular Scale
  • Slide 13
  • Entropy Changes
  • Third Law of Thermodynamics
  • Standard Entropies
  • Standard Entropies (298 K) from Absolute Entropies (0K)
  • Entropy Changes in the System
  • Slide 19
  • Thermodynamic Changes in Systems (Chem Reactions)
  • Entropy Changes in the Surroundings
  • Entropy Change in the Universe
  • Slide 23
  • Gibbs Free Energy (G)
  • Free Energy Changes
  • Spontaneity Enthalpy amp Entropy
  • Slide 27
  • Problems
  • Standard Free Energy Changes
  • Slide 30
  • Fourth Law of Thermodynamics Emergence
  • Slide 32
  • Slide 33
  • Slide 34
  • Slide 35
  • Slide 36
  • Slide 37
  • Slide 38
  • Slide 39
  • Slide 40
  • Slide 41
  • Slide 42
  • Slide 43
  • Slide 44
  • Slide 45
  • Slide 46
  • Slide 47
  • Slide 48
  • Slide 49
  • 2006 (B)
  • Slide 51
  • Slide 52
  • Slide 53
  • Slide 54
  • Slide 55
Page 29: Unit 14: Chemical Thermodynamics

ChemicalThermodynamics

Standard Free Energy Changes

Analogous to standard enthalpies of formation are standard free energies of formation G

f

G = nG(products) mGf (reactants)f

where n and m are the stoichiometric coefficients

ChemicalThermodynamics

Standard Free Energy Changes

12 CO2(g) + 6 H2O(g)2 C6H6 (l) + 15 O2 (g)

Grxn = nG(prod) mG(react)f

Calculate the standard free energy changes for the above reaction 25 degC

f

[12(-394) + 6(-229)] ndash [2(125) + 15 (0)]

ndash [2 C6H6 (l) + 15 O2(g)][12 CO2(g) + 6 H2O(g)]

Grxn = - 6352 Jmol K

Standard Molar Gibbs Energy of Formation (Gdegf)

CO2 (g) -394

H2O (g) -229

C6H6 (l) 125

ChemicalThermodynamics

Fourth Law of Thermodynamics EmergenceComplex emergent systems spontaneously (-G) arise when energy flows through a collection of many interacting particles resulting in new patterns of complex behaviors that are much more than the sum of the individual parts (+S)

The formation of these complex patterns in emergent systems is more efficient in the dissipation of energy (-H) thus speeds up the increase of entropy in the universe

G = H -TSA precise definition of emergence and a useful mathematical formulation of this phenomenon remains elusive

C f [n i E(t)]Examples cells forming living organisms stars forming galaxies neurons forming conscious brain

ChemicalThermodynamics

ChemicalThermodynamics

ChemicalThermodynamics

ChemicalThermodynamics

ChemicalThermodynamics

ChemicalThermodynamics

ChemicalThermodynamics

2002 B

ChemicalThermodynamics

ChemicalThermodynamics

ChemicalThermodynamics

2003 A

ChemicalThermodynamics

ChemicalThermodynamics

2004 A

ChemicalThermodynamics

ChemicalThermodynamics

ChemicalThermodynamics

2004 B

ChemicalThermodynamics

ChemicalThermodynamics

2005 A

ChemicalThermodynamics

ChemicalThermodynamics

2006 (B)

ChemicalThermodynamics

ChemicalThermodynamics

ChemicalThermodynamics

2007 (A)

ChemicalThermodynamics

ChemicalThermodynamics

  • Unit 14 Chemical Thermodynamics
  • First Law of Thermodynamics
  • Second Law of Thermodynamics
  • Spontaneous Processes
  • Slide 5
  • Spontaneity
  • Irreversible Processes
  • Entropy (S)
  • Slide 9
  • Second Law of Thermodynamics
  • Slide 11
  • Entropy on the Molecular Scale
  • Slide 13
  • Entropy Changes
  • Third Law of Thermodynamics
  • Standard Entropies
  • Standard Entropies (298 K) from Absolute Entropies (0K)
  • Entropy Changes in the System
  • Slide 19
  • Thermodynamic Changes in Systems (Chem Reactions)
  • Entropy Changes in the Surroundings
  • Entropy Change in the Universe
  • Slide 23
  • Gibbs Free Energy (G)
  • Free Energy Changes
  • Spontaneity Enthalpy amp Entropy
  • Slide 27
  • Problems
  • Standard Free Energy Changes
  • Slide 30
  • Fourth Law of Thermodynamics Emergence
  • Slide 32
  • Slide 33
  • Slide 34
  • Slide 35
  • Slide 36
  • Slide 37
  • Slide 38
  • Slide 39
  • Slide 40
  • Slide 41
  • Slide 42
  • Slide 43
  • Slide 44
  • Slide 45
  • Slide 46
  • Slide 47
  • Slide 48
  • Slide 49
  • 2006 (B)
  • Slide 51
  • Slide 52
  • Slide 53
  • Slide 54
  • Slide 55
Page 30: Unit 14: Chemical Thermodynamics

ChemicalThermodynamics

Standard Free Energy Changes

12 CO2(g) + 6 H2O(g)2 C6H6 (l) + 15 O2 (g)

Grxn = nG(prod) mG(react)f

Calculate the standard free energy changes for the above reaction 25 degC

f

[12(-394) + 6(-229)] ndash [2(125) + 15 (0)]

ndash [2 C6H6 (l) + 15 O2(g)][12 CO2(g) + 6 H2O(g)]

Grxn = - 6352 Jmol K

Standard Molar Gibbs Energy of Formation (Gdegf)

CO2 (g) -394

H2O (g) -229

C6H6 (l) 125

ChemicalThermodynamics

Fourth Law of Thermodynamics EmergenceComplex emergent systems spontaneously (-G) arise when energy flows through a collection of many interacting particles resulting in new patterns of complex behaviors that are much more than the sum of the individual parts (+S)

The formation of these complex patterns in emergent systems is more efficient in the dissipation of energy (-H) thus speeds up the increase of entropy in the universe

G = H -TSA precise definition of emergence and a useful mathematical formulation of this phenomenon remains elusive

C f [n i E(t)]Examples cells forming living organisms stars forming galaxies neurons forming conscious brain

ChemicalThermodynamics

ChemicalThermodynamics

ChemicalThermodynamics

ChemicalThermodynamics

ChemicalThermodynamics

ChemicalThermodynamics

ChemicalThermodynamics

2002 B

ChemicalThermodynamics

ChemicalThermodynamics

ChemicalThermodynamics

2003 A

ChemicalThermodynamics

ChemicalThermodynamics

2004 A

ChemicalThermodynamics

ChemicalThermodynamics

ChemicalThermodynamics

2004 B

ChemicalThermodynamics

ChemicalThermodynamics

2005 A

ChemicalThermodynamics

ChemicalThermodynamics

2006 (B)

ChemicalThermodynamics

ChemicalThermodynamics

ChemicalThermodynamics

2007 (A)

ChemicalThermodynamics

ChemicalThermodynamics

  • Unit 14 Chemical Thermodynamics
  • First Law of Thermodynamics
  • Second Law of Thermodynamics
  • Spontaneous Processes
  • Slide 5
  • Spontaneity
  • Irreversible Processes
  • Entropy (S)
  • Slide 9
  • Second Law of Thermodynamics
  • Slide 11
  • Entropy on the Molecular Scale
  • Slide 13
  • Entropy Changes
  • Third Law of Thermodynamics
  • Standard Entropies
  • Standard Entropies (298 K) from Absolute Entropies (0K)
  • Entropy Changes in the System
  • Slide 19
  • Thermodynamic Changes in Systems (Chem Reactions)
  • Entropy Changes in the Surroundings
  • Entropy Change in the Universe
  • Slide 23
  • Gibbs Free Energy (G)
  • Free Energy Changes
  • Spontaneity Enthalpy amp Entropy
  • Slide 27
  • Problems
  • Standard Free Energy Changes
  • Slide 30
  • Fourth Law of Thermodynamics Emergence
  • Slide 32
  • Slide 33
  • Slide 34
  • Slide 35
  • Slide 36
  • Slide 37
  • Slide 38
  • Slide 39
  • Slide 40
  • Slide 41
  • Slide 42
  • Slide 43
  • Slide 44
  • Slide 45
  • Slide 46
  • Slide 47
  • Slide 48
  • Slide 49
  • 2006 (B)
  • Slide 51
  • Slide 52
  • Slide 53
  • Slide 54
  • Slide 55
Page 31: Unit 14: Chemical Thermodynamics

ChemicalThermodynamics

Fourth Law of Thermodynamics EmergenceComplex emergent systems spontaneously (-G) arise when energy flows through a collection of many interacting particles resulting in new patterns of complex behaviors that are much more than the sum of the individual parts (+S)

The formation of these complex patterns in emergent systems is more efficient in the dissipation of energy (-H) thus speeds up the increase of entropy in the universe

G = H -TSA precise definition of emergence and a useful mathematical formulation of this phenomenon remains elusive

C f [n i E(t)]Examples cells forming living organisms stars forming galaxies neurons forming conscious brain

ChemicalThermodynamics

ChemicalThermodynamics

ChemicalThermodynamics

ChemicalThermodynamics

ChemicalThermodynamics

ChemicalThermodynamics

ChemicalThermodynamics

2002 B

ChemicalThermodynamics

ChemicalThermodynamics

ChemicalThermodynamics

2003 A

ChemicalThermodynamics

ChemicalThermodynamics

2004 A

ChemicalThermodynamics

ChemicalThermodynamics

ChemicalThermodynamics

2004 B

ChemicalThermodynamics

ChemicalThermodynamics

2005 A

ChemicalThermodynamics

ChemicalThermodynamics

2006 (B)

ChemicalThermodynamics

ChemicalThermodynamics

ChemicalThermodynamics

2007 (A)

ChemicalThermodynamics

ChemicalThermodynamics

  • Unit 14 Chemical Thermodynamics
  • First Law of Thermodynamics
  • Second Law of Thermodynamics
  • Spontaneous Processes
  • Slide 5
  • Spontaneity
  • Irreversible Processes
  • Entropy (S)
  • Slide 9
  • Second Law of Thermodynamics
  • Slide 11
  • Entropy on the Molecular Scale
  • Slide 13
  • Entropy Changes
  • Third Law of Thermodynamics
  • Standard Entropies
  • Standard Entropies (298 K) from Absolute Entropies (0K)
  • Entropy Changes in the System
  • Slide 19
  • Thermodynamic Changes in Systems (Chem Reactions)
  • Entropy Changes in the Surroundings
  • Entropy Change in the Universe
  • Slide 23
  • Gibbs Free Energy (G)
  • Free Energy Changes
  • Spontaneity Enthalpy amp Entropy
  • Slide 27
  • Problems
  • Standard Free Energy Changes
  • Slide 30
  • Fourth Law of Thermodynamics Emergence
  • Slide 32
  • Slide 33
  • Slide 34
  • Slide 35
  • Slide 36
  • Slide 37
  • Slide 38
  • Slide 39
  • Slide 40
  • Slide 41
  • Slide 42
  • Slide 43
  • Slide 44
  • Slide 45
  • Slide 46
  • Slide 47
  • Slide 48
  • Slide 49
  • 2006 (B)
  • Slide 51
  • Slide 52
  • Slide 53
  • Slide 54
  • Slide 55
Page 32: Unit 14: Chemical Thermodynamics

ChemicalThermodynamics

ChemicalThermodynamics

ChemicalThermodynamics

ChemicalThermodynamics

ChemicalThermodynamics

ChemicalThermodynamics

ChemicalThermodynamics

2002 B

ChemicalThermodynamics

ChemicalThermodynamics

ChemicalThermodynamics

2003 A

ChemicalThermodynamics

ChemicalThermodynamics

2004 A

ChemicalThermodynamics

ChemicalThermodynamics

ChemicalThermodynamics

2004 B

ChemicalThermodynamics

ChemicalThermodynamics

2005 A

ChemicalThermodynamics

ChemicalThermodynamics

2006 (B)

ChemicalThermodynamics

ChemicalThermodynamics

ChemicalThermodynamics

2007 (A)

ChemicalThermodynamics

ChemicalThermodynamics

  • Unit 14 Chemical Thermodynamics
  • First Law of Thermodynamics
  • Second Law of Thermodynamics
  • Spontaneous Processes
  • Slide 5
  • Spontaneity
  • Irreversible Processes
  • Entropy (S)
  • Slide 9
  • Second Law of Thermodynamics
  • Slide 11
  • Entropy on the Molecular Scale
  • Slide 13
  • Entropy Changes
  • Third Law of Thermodynamics
  • Standard Entropies
  • Standard Entropies (298 K) from Absolute Entropies (0K)
  • Entropy Changes in the System
  • Slide 19
  • Thermodynamic Changes in Systems (Chem Reactions)
  • Entropy Changes in the Surroundings
  • Entropy Change in the Universe
  • Slide 23
  • Gibbs Free Energy (G)
  • Free Energy Changes
  • Spontaneity Enthalpy amp Entropy
  • Slide 27
  • Problems
  • Standard Free Energy Changes
  • Slide 30
  • Fourth Law of Thermodynamics Emergence
  • Slide 32
  • Slide 33
  • Slide 34
  • Slide 35
  • Slide 36
  • Slide 37
  • Slide 38
  • Slide 39
  • Slide 40
  • Slide 41
  • Slide 42
  • Slide 43
  • Slide 44
  • Slide 45
  • Slide 46
  • Slide 47
  • Slide 48
  • Slide 49
  • 2006 (B)
  • Slide 51
  • Slide 52
  • Slide 53
  • Slide 54
  • Slide 55
Page 33: Unit 14: Chemical Thermodynamics

ChemicalThermodynamics

ChemicalThermodynamics

ChemicalThermodynamics

ChemicalThermodynamics

ChemicalThermodynamics

ChemicalThermodynamics

2002 B

ChemicalThermodynamics

ChemicalThermodynamics

ChemicalThermodynamics

2003 A

ChemicalThermodynamics

ChemicalThermodynamics

2004 A

ChemicalThermodynamics

ChemicalThermodynamics

ChemicalThermodynamics

2004 B

ChemicalThermodynamics

ChemicalThermodynamics

2005 A

ChemicalThermodynamics

ChemicalThermodynamics

2006 (B)

ChemicalThermodynamics

ChemicalThermodynamics

ChemicalThermodynamics

2007 (A)

ChemicalThermodynamics

ChemicalThermodynamics

  • Unit 14 Chemical Thermodynamics
  • First Law of Thermodynamics
  • Second Law of Thermodynamics
  • Spontaneous Processes
  • Slide 5
  • Spontaneity
  • Irreversible Processes
  • Entropy (S)
  • Slide 9
  • Second Law of Thermodynamics
  • Slide 11
  • Entropy on the Molecular Scale
  • Slide 13
  • Entropy Changes
  • Third Law of Thermodynamics
  • Standard Entropies
  • Standard Entropies (298 K) from Absolute Entropies (0K)
  • Entropy Changes in the System
  • Slide 19
  • Thermodynamic Changes in Systems (Chem Reactions)
  • Entropy Changes in the Surroundings
  • Entropy Change in the Universe
  • Slide 23
  • Gibbs Free Energy (G)
  • Free Energy Changes
  • Spontaneity Enthalpy amp Entropy
  • Slide 27
  • Problems
  • Standard Free Energy Changes
  • Slide 30
  • Fourth Law of Thermodynamics Emergence
  • Slide 32
  • Slide 33
  • Slide 34
  • Slide 35
  • Slide 36
  • Slide 37
  • Slide 38
  • Slide 39
  • Slide 40
  • Slide 41
  • Slide 42
  • Slide 43
  • Slide 44
  • Slide 45
  • Slide 46
  • Slide 47
  • Slide 48
  • Slide 49
  • 2006 (B)
  • Slide 51
  • Slide 52
  • Slide 53
  • Slide 54
  • Slide 55
Page 34: Unit 14: Chemical Thermodynamics

ChemicalThermodynamics

ChemicalThermodynamics

ChemicalThermodynamics

ChemicalThermodynamics

ChemicalThermodynamics

2002 B

ChemicalThermodynamics

ChemicalThermodynamics

ChemicalThermodynamics

2003 A

ChemicalThermodynamics

ChemicalThermodynamics

2004 A

ChemicalThermodynamics

ChemicalThermodynamics

ChemicalThermodynamics

2004 B

ChemicalThermodynamics

ChemicalThermodynamics

2005 A

ChemicalThermodynamics

ChemicalThermodynamics

2006 (B)

ChemicalThermodynamics

ChemicalThermodynamics

ChemicalThermodynamics

2007 (A)

ChemicalThermodynamics

ChemicalThermodynamics

  • Unit 14 Chemical Thermodynamics
  • First Law of Thermodynamics
  • Second Law of Thermodynamics
  • Spontaneous Processes
  • Slide 5
  • Spontaneity
  • Irreversible Processes
  • Entropy (S)
  • Slide 9
  • Second Law of Thermodynamics
  • Slide 11
  • Entropy on the Molecular Scale
  • Slide 13
  • Entropy Changes
  • Third Law of Thermodynamics
  • Standard Entropies
  • Standard Entropies (298 K) from Absolute Entropies (0K)
  • Entropy Changes in the System
  • Slide 19
  • Thermodynamic Changes in Systems (Chem Reactions)
  • Entropy Changes in the Surroundings
  • Entropy Change in the Universe
  • Slide 23
  • Gibbs Free Energy (G)
  • Free Energy Changes
  • Spontaneity Enthalpy amp Entropy
  • Slide 27
  • Problems
  • Standard Free Energy Changes
  • Slide 30
  • Fourth Law of Thermodynamics Emergence
  • Slide 32
  • Slide 33
  • Slide 34
  • Slide 35
  • Slide 36
  • Slide 37
  • Slide 38
  • Slide 39
  • Slide 40
  • Slide 41
  • Slide 42
  • Slide 43
  • Slide 44
  • Slide 45
  • Slide 46
  • Slide 47
  • Slide 48
  • Slide 49
  • 2006 (B)
  • Slide 51
  • Slide 52
  • Slide 53
  • Slide 54
  • Slide 55
Page 35: Unit 14: Chemical Thermodynamics

ChemicalThermodynamics

ChemicalThermodynamics

ChemicalThermodynamics

ChemicalThermodynamics

2002 B

ChemicalThermodynamics

ChemicalThermodynamics

ChemicalThermodynamics

2003 A

ChemicalThermodynamics

ChemicalThermodynamics

2004 A

ChemicalThermodynamics

ChemicalThermodynamics

ChemicalThermodynamics

2004 B

ChemicalThermodynamics

ChemicalThermodynamics

2005 A

ChemicalThermodynamics

ChemicalThermodynamics

2006 (B)

ChemicalThermodynamics

ChemicalThermodynamics

ChemicalThermodynamics

2007 (A)

ChemicalThermodynamics

ChemicalThermodynamics

  • Unit 14 Chemical Thermodynamics
  • First Law of Thermodynamics
  • Second Law of Thermodynamics
  • Spontaneous Processes
  • Slide 5
  • Spontaneity
  • Irreversible Processes
  • Entropy (S)
  • Slide 9
  • Second Law of Thermodynamics
  • Slide 11
  • Entropy on the Molecular Scale
  • Slide 13
  • Entropy Changes
  • Third Law of Thermodynamics
  • Standard Entropies
  • Standard Entropies (298 K) from Absolute Entropies (0K)
  • Entropy Changes in the System
  • Slide 19
  • Thermodynamic Changes in Systems (Chem Reactions)
  • Entropy Changes in the Surroundings
  • Entropy Change in the Universe
  • Slide 23
  • Gibbs Free Energy (G)
  • Free Energy Changes
  • Spontaneity Enthalpy amp Entropy
  • Slide 27
  • Problems
  • Standard Free Energy Changes
  • Slide 30
  • Fourth Law of Thermodynamics Emergence
  • Slide 32
  • Slide 33
  • Slide 34
  • Slide 35
  • Slide 36
  • Slide 37
  • Slide 38
  • Slide 39
  • Slide 40
  • Slide 41
  • Slide 42
  • Slide 43
  • Slide 44
  • Slide 45
  • Slide 46
  • Slide 47
  • Slide 48
  • Slide 49
  • 2006 (B)
  • Slide 51
  • Slide 52
  • Slide 53
  • Slide 54
  • Slide 55
Page 36: Unit 14: Chemical Thermodynamics

ChemicalThermodynamics

ChemicalThermodynamics

ChemicalThermodynamics

2002 B

ChemicalThermodynamics

ChemicalThermodynamics

ChemicalThermodynamics

2003 A

ChemicalThermodynamics

ChemicalThermodynamics

2004 A

ChemicalThermodynamics

ChemicalThermodynamics

ChemicalThermodynamics

2004 B

ChemicalThermodynamics

ChemicalThermodynamics

2005 A

ChemicalThermodynamics

ChemicalThermodynamics

2006 (B)

ChemicalThermodynamics

ChemicalThermodynamics

ChemicalThermodynamics

2007 (A)

ChemicalThermodynamics

ChemicalThermodynamics

  • Unit 14 Chemical Thermodynamics
  • First Law of Thermodynamics
  • Second Law of Thermodynamics
  • Spontaneous Processes
  • Slide 5
  • Spontaneity
  • Irreversible Processes
  • Entropy (S)
  • Slide 9
  • Second Law of Thermodynamics
  • Slide 11
  • Entropy on the Molecular Scale
  • Slide 13
  • Entropy Changes
  • Third Law of Thermodynamics
  • Standard Entropies
  • Standard Entropies (298 K) from Absolute Entropies (0K)
  • Entropy Changes in the System
  • Slide 19
  • Thermodynamic Changes in Systems (Chem Reactions)
  • Entropy Changes in the Surroundings
  • Entropy Change in the Universe
  • Slide 23
  • Gibbs Free Energy (G)
  • Free Energy Changes
  • Spontaneity Enthalpy amp Entropy
  • Slide 27
  • Problems
  • Standard Free Energy Changes
  • Slide 30
  • Fourth Law of Thermodynamics Emergence
  • Slide 32
  • Slide 33
  • Slide 34
  • Slide 35
  • Slide 36
  • Slide 37
  • Slide 38
  • Slide 39
  • Slide 40
  • Slide 41
  • Slide 42
  • Slide 43
  • Slide 44
  • Slide 45
  • Slide 46
  • Slide 47
  • Slide 48
  • Slide 49
  • 2006 (B)
  • Slide 51
  • Slide 52
  • Slide 53
  • Slide 54
  • Slide 55
Page 37: Unit 14: Chemical Thermodynamics

ChemicalThermodynamics

ChemicalThermodynamics

2002 B

ChemicalThermodynamics

ChemicalThermodynamics

ChemicalThermodynamics

2003 A

ChemicalThermodynamics

ChemicalThermodynamics

2004 A

ChemicalThermodynamics

ChemicalThermodynamics

ChemicalThermodynamics

2004 B

ChemicalThermodynamics

ChemicalThermodynamics

2005 A

ChemicalThermodynamics

ChemicalThermodynamics

2006 (B)

ChemicalThermodynamics

ChemicalThermodynamics

ChemicalThermodynamics

2007 (A)

ChemicalThermodynamics

ChemicalThermodynamics

  • Unit 14 Chemical Thermodynamics
  • First Law of Thermodynamics
  • Second Law of Thermodynamics
  • Spontaneous Processes
  • Slide 5
  • Spontaneity
  • Irreversible Processes
  • Entropy (S)
  • Slide 9
  • Second Law of Thermodynamics
  • Slide 11
  • Entropy on the Molecular Scale
  • Slide 13
  • Entropy Changes
  • Third Law of Thermodynamics
  • Standard Entropies
  • Standard Entropies (298 K) from Absolute Entropies (0K)
  • Entropy Changes in the System
  • Slide 19
  • Thermodynamic Changes in Systems (Chem Reactions)
  • Entropy Changes in the Surroundings
  • Entropy Change in the Universe
  • Slide 23
  • Gibbs Free Energy (G)
  • Free Energy Changes
  • Spontaneity Enthalpy amp Entropy
  • Slide 27
  • Problems
  • Standard Free Energy Changes
  • Slide 30
  • Fourth Law of Thermodynamics Emergence
  • Slide 32
  • Slide 33
  • Slide 34
  • Slide 35
  • Slide 36
  • Slide 37
  • Slide 38
  • Slide 39
  • Slide 40
  • Slide 41
  • Slide 42
  • Slide 43
  • Slide 44
  • Slide 45
  • Slide 46
  • Slide 47
  • Slide 48
  • Slide 49
  • 2006 (B)
  • Slide 51
  • Slide 52
  • Slide 53
  • Slide 54
  • Slide 55
Page 38: Unit 14: Chemical Thermodynamics

ChemicalThermodynamics

2002 B

ChemicalThermodynamics

ChemicalThermodynamics

ChemicalThermodynamics

2003 A

ChemicalThermodynamics

ChemicalThermodynamics

2004 A

ChemicalThermodynamics

ChemicalThermodynamics

ChemicalThermodynamics

2004 B

ChemicalThermodynamics

ChemicalThermodynamics

2005 A

ChemicalThermodynamics

ChemicalThermodynamics

2006 (B)

ChemicalThermodynamics

ChemicalThermodynamics

ChemicalThermodynamics

2007 (A)

ChemicalThermodynamics

ChemicalThermodynamics

  • Unit 14 Chemical Thermodynamics
  • First Law of Thermodynamics
  • Second Law of Thermodynamics
  • Spontaneous Processes
  • Slide 5
  • Spontaneity
  • Irreversible Processes
  • Entropy (S)
  • Slide 9
  • Second Law of Thermodynamics
  • Slide 11
  • Entropy on the Molecular Scale
  • Slide 13
  • Entropy Changes
  • Third Law of Thermodynamics
  • Standard Entropies
  • Standard Entropies (298 K) from Absolute Entropies (0K)
  • Entropy Changes in the System
  • Slide 19
  • Thermodynamic Changes in Systems (Chem Reactions)
  • Entropy Changes in the Surroundings
  • Entropy Change in the Universe
  • Slide 23
  • Gibbs Free Energy (G)
  • Free Energy Changes
  • Spontaneity Enthalpy amp Entropy
  • Slide 27
  • Problems
  • Standard Free Energy Changes
  • Slide 30
  • Fourth Law of Thermodynamics Emergence
  • Slide 32
  • Slide 33
  • Slide 34
  • Slide 35
  • Slide 36
  • Slide 37
  • Slide 38
  • Slide 39
  • Slide 40
  • Slide 41
  • Slide 42
  • Slide 43
  • Slide 44
  • Slide 45
  • Slide 46
  • Slide 47
  • Slide 48
  • Slide 49
  • 2006 (B)
  • Slide 51
  • Slide 52
  • Slide 53
  • Slide 54
  • Slide 55
Page 39: Unit 14: Chemical Thermodynamics

ChemicalThermodynamics

ChemicalThermodynamics

ChemicalThermodynamics

2003 A

ChemicalThermodynamics

ChemicalThermodynamics

2004 A

ChemicalThermodynamics

ChemicalThermodynamics

ChemicalThermodynamics

2004 B

ChemicalThermodynamics

ChemicalThermodynamics

2005 A

ChemicalThermodynamics

ChemicalThermodynamics

2006 (B)

ChemicalThermodynamics

ChemicalThermodynamics

ChemicalThermodynamics

2007 (A)

ChemicalThermodynamics

ChemicalThermodynamics

  • Unit 14 Chemical Thermodynamics
  • First Law of Thermodynamics
  • Second Law of Thermodynamics
  • Spontaneous Processes
  • Slide 5
  • Spontaneity
  • Irreversible Processes
  • Entropy (S)
  • Slide 9
  • Second Law of Thermodynamics
  • Slide 11
  • Entropy on the Molecular Scale
  • Slide 13
  • Entropy Changes
  • Third Law of Thermodynamics
  • Standard Entropies
  • Standard Entropies (298 K) from Absolute Entropies (0K)
  • Entropy Changes in the System
  • Slide 19
  • Thermodynamic Changes in Systems (Chem Reactions)
  • Entropy Changes in the Surroundings
  • Entropy Change in the Universe
  • Slide 23
  • Gibbs Free Energy (G)
  • Free Energy Changes
  • Spontaneity Enthalpy amp Entropy
  • Slide 27
  • Problems
  • Standard Free Energy Changes
  • Slide 30
  • Fourth Law of Thermodynamics Emergence
  • Slide 32
  • Slide 33
  • Slide 34
  • Slide 35
  • Slide 36
  • Slide 37
  • Slide 38
  • Slide 39
  • Slide 40
  • Slide 41
  • Slide 42
  • Slide 43
  • Slide 44
  • Slide 45
  • Slide 46
  • Slide 47
  • Slide 48
  • Slide 49
  • 2006 (B)
  • Slide 51
  • Slide 52
  • Slide 53
  • Slide 54
  • Slide 55
Page 40: Unit 14: Chemical Thermodynamics

ChemicalThermodynamics

ChemicalThermodynamics

2003 A

ChemicalThermodynamics

ChemicalThermodynamics

2004 A

ChemicalThermodynamics

ChemicalThermodynamics

ChemicalThermodynamics

2004 B

ChemicalThermodynamics

ChemicalThermodynamics

2005 A

ChemicalThermodynamics

ChemicalThermodynamics

2006 (B)

ChemicalThermodynamics

ChemicalThermodynamics

ChemicalThermodynamics

2007 (A)

ChemicalThermodynamics

ChemicalThermodynamics

  • Unit 14 Chemical Thermodynamics
  • First Law of Thermodynamics
  • Second Law of Thermodynamics
  • Spontaneous Processes
  • Slide 5
  • Spontaneity
  • Irreversible Processes
  • Entropy (S)
  • Slide 9
  • Second Law of Thermodynamics
  • Slide 11
  • Entropy on the Molecular Scale
  • Slide 13
  • Entropy Changes
  • Third Law of Thermodynamics
  • Standard Entropies
  • Standard Entropies (298 K) from Absolute Entropies (0K)
  • Entropy Changes in the System
  • Slide 19
  • Thermodynamic Changes in Systems (Chem Reactions)
  • Entropy Changes in the Surroundings
  • Entropy Change in the Universe
  • Slide 23
  • Gibbs Free Energy (G)
  • Free Energy Changes
  • Spontaneity Enthalpy amp Entropy
  • Slide 27
  • Problems
  • Standard Free Energy Changes
  • Slide 30
  • Fourth Law of Thermodynamics Emergence
  • Slide 32
  • Slide 33
  • Slide 34
  • Slide 35
  • Slide 36
  • Slide 37
  • Slide 38
  • Slide 39
  • Slide 40
  • Slide 41
  • Slide 42
  • Slide 43
  • Slide 44
  • Slide 45
  • Slide 46
  • Slide 47
  • Slide 48
  • Slide 49
  • 2006 (B)
  • Slide 51
  • Slide 52
  • Slide 53
  • Slide 54
  • Slide 55
Page 41: Unit 14: Chemical Thermodynamics

ChemicalThermodynamics

2003 A

ChemicalThermodynamics

ChemicalThermodynamics

2004 A

ChemicalThermodynamics

ChemicalThermodynamics

ChemicalThermodynamics

2004 B

ChemicalThermodynamics

ChemicalThermodynamics

2005 A

ChemicalThermodynamics

ChemicalThermodynamics

2006 (B)

ChemicalThermodynamics

ChemicalThermodynamics

ChemicalThermodynamics

2007 (A)

ChemicalThermodynamics

ChemicalThermodynamics

  • Unit 14 Chemical Thermodynamics
  • First Law of Thermodynamics
  • Second Law of Thermodynamics
  • Spontaneous Processes
  • Slide 5
  • Spontaneity
  • Irreversible Processes
  • Entropy (S)
  • Slide 9
  • Second Law of Thermodynamics
  • Slide 11
  • Entropy on the Molecular Scale
  • Slide 13
  • Entropy Changes
  • Third Law of Thermodynamics
  • Standard Entropies
  • Standard Entropies (298 K) from Absolute Entropies (0K)
  • Entropy Changes in the System
  • Slide 19
  • Thermodynamic Changes in Systems (Chem Reactions)
  • Entropy Changes in the Surroundings
  • Entropy Change in the Universe
  • Slide 23
  • Gibbs Free Energy (G)
  • Free Energy Changes
  • Spontaneity Enthalpy amp Entropy
  • Slide 27
  • Problems
  • Standard Free Energy Changes
  • Slide 30
  • Fourth Law of Thermodynamics Emergence
  • Slide 32
  • Slide 33
  • Slide 34
  • Slide 35
  • Slide 36
  • Slide 37
  • Slide 38
  • Slide 39
  • Slide 40
  • Slide 41
  • Slide 42
  • Slide 43
  • Slide 44
  • Slide 45
  • Slide 46
  • Slide 47
  • Slide 48
  • Slide 49
  • 2006 (B)
  • Slide 51
  • Slide 52
  • Slide 53
  • Slide 54
  • Slide 55
Page 42: Unit 14: Chemical Thermodynamics

ChemicalThermodynamics

ChemicalThermodynamics

2004 A

ChemicalThermodynamics

ChemicalThermodynamics

ChemicalThermodynamics

2004 B

ChemicalThermodynamics

ChemicalThermodynamics

2005 A

ChemicalThermodynamics

ChemicalThermodynamics

2006 (B)

ChemicalThermodynamics

ChemicalThermodynamics

ChemicalThermodynamics

2007 (A)

ChemicalThermodynamics

ChemicalThermodynamics

  • Unit 14 Chemical Thermodynamics
  • First Law of Thermodynamics
  • Second Law of Thermodynamics
  • Spontaneous Processes
  • Slide 5
  • Spontaneity
  • Irreversible Processes
  • Entropy (S)
  • Slide 9
  • Second Law of Thermodynamics
  • Slide 11
  • Entropy on the Molecular Scale
  • Slide 13
  • Entropy Changes
  • Third Law of Thermodynamics
  • Standard Entropies
  • Standard Entropies (298 K) from Absolute Entropies (0K)
  • Entropy Changes in the System
  • Slide 19
  • Thermodynamic Changes in Systems (Chem Reactions)
  • Entropy Changes in the Surroundings
  • Entropy Change in the Universe
  • Slide 23
  • Gibbs Free Energy (G)
  • Free Energy Changes
  • Spontaneity Enthalpy amp Entropy
  • Slide 27
  • Problems
  • Standard Free Energy Changes
  • Slide 30
  • Fourth Law of Thermodynamics Emergence
  • Slide 32
  • Slide 33
  • Slide 34
  • Slide 35
  • Slide 36
  • Slide 37
  • Slide 38
  • Slide 39
  • Slide 40
  • Slide 41
  • Slide 42
  • Slide 43
  • Slide 44
  • Slide 45
  • Slide 46
  • Slide 47
  • Slide 48
  • Slide 49
  • 2006 (B)
  • Slide 51
  • Slide 52
  • Slide 53
  • Slide 54
  • Slide 55
Page 43: Unit 14: Chemical Thermodynamics

ChemicalThermodynamics

2004 A

ChemicalThermodynamics

ChemicalThermodynamics

ChemicalThermodynamics

2004 B

ChemicalThermodynamics

ChemicalThermodynamics

2005 A

ChemicalThermodynamics

ChemicalThermodynamics

2006 (B)

ChemicalThermodynamics

ChemicalThermodynamics

ChemicalThermodynamics

2007 (A)

ChemicalThermodynamics

ChemicalThermodynamics

  • Unit 14 Chemical Thermodynamics
  • First Law of Thermodynamics
  • Second Law of Thermodynamics
  • Spontaneous Processes
  • Slide 5
  • Spontaneity
  • Irreversible Processes
  • Entropy (S)
  • Slide 9
  • Second Law of Thermodynamics
  • Slide 11
  • Entropy on the Molecular Scale
  • Slide 13
  • Entropy Changes
  • Third Law of Thermodynamics
  • Standard Entropies
  • Standard Entropies (298 K) from Absolute Entropies (0K)
  • Entropy Changes in the System
  • Slide 19
  • Thermodynamic Changes in Systems (Chem Reactions)
  • Entropy Changes in the Surroundings
  • Entropy Change in the Universe
  • Slide 23
  • Gibbs Free Energy (G)
  • Free Energy Changes
  • Spontaneity Enthalpy amp Entropy
  • Slide 27
  • Problems
  • Standard Free Energy Changes
  • Slide 30
  • Fourth Law of Thermodynamics Emergence
  • Slide 32
  • Slide 33
  • Slide 34
  • Slide 35
  • Slide 36
  • Slide 37
  • Slide 38
  • Slide 39
  • Slide 40
  • Slide 41
  • Slide 42
  • Slide 43
  • Slide 44
  • Slide 45
  • Slide 46
  • Slide 47
  • Slide 48
  • Slide 49
  • 2006 (B)
  • Slide 51
  • Slide 52
  • Slide 53
  • Slide 54
  • Slide 55
Page 44: Unit 14: Chemical Thermodynamics

ChemicalThermodynamics

ChemicalThermodynamics

ChemicalThermodynamics

2004 B

ChemicalThermodynamics

ChemicalThermodynamics

2005 A

ChemicalThermodynamics

ChemicalThermodynamics

2006 (B)

ChemicalThermodynamics

ChemicalThermodynamics

ChemicalThermodynamics

2007 (A)

ChemicalThermodynamics

ChemicalThermodynamics

  • Unit 14 Chemical Thermodynamics
  • First Law of Thermodynamics
  • Second Law of Thermodynamics
  • Spontaneous Processes
  • Slide 5
  • Spontaneity
  • Irreversible Processes
  • Entropy (S)
  • Slide 9
  • Second Law of Thermodynamics
  • Slide 11
  • Entropy on the Molecular Scale
  • Slide 13
  • Entropy Changes
  • Third Law of Thermodynamics
  • Standard Entropies
  • Standard Entropies (298 K) from Absolute Entropies (0K)
  • Entropy Changes in the System
  • Slide 19
  • Thermodynamic Changes in Systems (Chem Reactions)
  • Entropy Changes in the Surroundings
  • Entropy Change in the Universe
  • Slide 23
  • Gibbs Free Energy (G)
  • Free Energy Changes
  • Spontaneity Enthalpy amp Entropy
  • Slide 27
  • Problems
  • Standard Free Energy Changes
  • Slide 30
  • Fourth Law of Thermodynamics Emergence
  • Slide 32
  • Slide 33
  • Slide 34
  • Slide 35
  • Slide 36
  • Slide 37
  • Slide 38
  • Slide 39
  • Slide 40
  • Slide 41
  • Slide 42
  • Slide 43
  • Slide 44
  • Slide 45
  • Slide 46
  • Slide 47
  • Slide 48
  • Slide 49
  • 2006 (B)
  • Slide 51
  • Slide 52
  • Slide 53
  • Slide 54
  • Slide 55
Page 45: Unit 14: Chemical Thermodynamics

ChemicalThermodynamics

ChemicalThermodynamics

2004 B

ChemicalThermodynamics

ChemicalThermodynamics

2005 A

ChemicalThermodynamics

ChemicalThermodynamics

2006 (B)

ChemicalThermodynamics

ChemicalThermodynamics

ChemicalThermodynamics

2007 (A)

ChemicalThermodynamics

ChemicalThermodynamics

  • Unit 14 Chemical Thermodynamics
  • First Law of Thermodynamics
  • Second Law of Thermodynamics
  • Spontaneous Processes
  • Slide 5
  • Spontaneity
  • Irreversible Processes
  • Entropy (S)
  • Slide 9
  • Second Law of Thermodynamics
  • Slide 11
  • Entropy on the Molecular Scale
  • Slide 13
  • Entropy Changes
  • Third Law of Thermodynamics
  • Standard Entropies
  • Standard Entropies (298 K) from Absolute Entropies (0K)
  • Entropy Changes in the System
  • Slide 19
  • Thermodynamic Changes in Systems (Chem Reactions)
  • Entropy Changes in the Surroundings
  • Entropy Change in the Universe
  • Slide 23
  • Gibbs Free Energy (G)
  • Free Energy Changes
  • Spontaneity Enthalpy amp Entropy
  • Slide 27
  • Problems
  • Standard Free Energy Changes
  • Slide 30
  • Fourth Law of Thermodynamics Emergence
  • Slide 32
  • Slide 33
  • Slide 34
  • Slide 35
  • Slide 36
  • Slide 37
  • Slide 38
  • Slide 39
  • Slide 40
  • Slide 41
  • Slide 42
  • Slide 43
  • Slide 44
  • Slide 45
  • Slide 46
  • Slide 47
  • Slide 48
  • Slide 49
  • 2006 (B)
  • Slide 51
  • Slide 52
  • Slide 53
  • Slide 54
  • Slide 55
Page 46: Unit 14: Chemical Thermodynamics

ChemicalThermodynamics

2004 B

ChemicalThermodynamics

ChemicalThermodynamics

2005 A

ChemicalThermodynamics

ChemicalThermodynamics

2006 (B)

ChemicalThermodynamics

ChemicalThermodynamics

ChemicalThermodynamics

2007 (A)

ChemicalThermodynamics

ChemicalThermodynamics

  • Unit 14 Chemical Thermodynamics
  • First Law of Thermodynamics
  • Second Law of Thermodynamics
  • Spontaneous Processes
  • Slide 5
  • Spontaneity
  • Irreversible Processes
  • Entropy (S)
  • Slide 9
  • Second Law of Thermodynamics
  • Slide 11
  • Entropy on the Molecular Scale
  • Slide 13
  • Entropy Changes
  • Third Law of Thermodynamics
  • Standard Entropies
  • Standard Entropies (298 K) from Absolute Entropies (0K)
  • Entropy Changes in the System
  • Slide 19
  • Thermodynamic Changes in Systems (Chem Reactions)
  • Entropy Changes in the Surroundings
  • Entropy Change in the Universe
  • Slide 23
  • Gibbs Free Energy (G)
  • Free Energy Changes
  • Spontaneity Enthalpy amp Entropy
  • Slide 27
  • Problems
  • Standard Free Energy Changes
  • Slide 30
  • Fourth Law of Thermodynamics Emergence
  • Slide 32
  • Slide 33
  • Slide 34
  • Slide 35
  • Slide 36
  • Slide 37
  • Slide 38
  • Slide 39
  • Slide 40
  • Slide 41
  • Slide 42
  • Slide 43
  • Slide 44
  • Slide 45
  • Slide 46
  • Slide 47
  • Slide 48
  • Slide 49
  • 2006 (B)
  • Slide 51
  • Slide 52
  • Slide 53
  • Slide 54
  • Slide 55
Page 47: Unit 14: Chemical Thermodynamics

ChemicalThermodynamics

ChemicalThermodynamics

2005 A

ChemicalThermodynamics

ChemicalThermodynamics

2006 (B)

ChemicalThermodynamics

ChemicalThermodynamics

ChemicalThermodynamics

2007 (A)

ChemicalThermodynamics

ChemicalThermodynamics

  • Unit 14 Chemical Thermodynamics
  • First Law of Thermodynamics
  • Second Law of Thermodynamics
  • Spontaneous Processes
  • Slide 5
  • Spontaneity
  • Irreversible Processes
  • Entropy (S)
  • Slide 9
  • Second Law of Thermodynamics
  • Slide 11
  • Entropy on the Molecular Scale
  • Slide 13
  • Entropy Changes
  • Third Law of Thermodynamics
  • Standard Entropies
  • Standard Entropies (298 K) from Absolute Entropies (0K)
  • Entropy Changes in the System
  • Slide 19
  • Thermodynamic Changes in Systems (Chem Reactions)
  • Entropy Changes in the Surroundings
  • Entropy Change in the Universe
  • Slide 23
  • Gibbs Free Energy (G)
  • Free Energy Changes
  • Spontaneity Enthalpy amp Entropy
  • Slide 27
  • Problems
  • Standard Free Energy Changes
  • Slide 30
  • Fourth Law of Thermodynamics Emergence
  • Slide 32
  • Slide 33
  • Slide 34
  • Slide 35
  • Slide 36
  • Slide 37
  • Slide 38
  • Slide 39
  • Slide 40
  • Slide 41
  • Slide 42
  • Slide 43
  • Slide 44
  • Slide 45
  • Slide 46
  • Slide 47
  • Slide 48
  • Slide 49
  • 2006 (B)
  • Slide 51
  • Slide 52
  • Slide 53
  • Slide 54
  • Slide 55
Page 48: Unit 14: Chemical Thermodynamics

ChemicalThermodynamics

2005 A

ChemicalThermodynamics

ChemicalThermodynamics

2006 (B)

ChemicalThermodynamics

ChemicalThermodynamics

ChemicalThermodynamics

2007 (A)

ChemicalThermodynamics

ChemicalThermodynamics

  • Unit 14 Chemical Thermodynamics
  • First Law of Thermodynamics
  • Second Law of Thermodynamics
  • Spontaneous Processes
  • Slide 5
  • Spontaneity
  • Irreversible Processes
  • Entropy (S)
  • Slide 9
  • Second Law of Thermodynamics
  • Slide 11
  • Entropy on the Molecular Scale
  • Slide 13
  • Entropy Changes
  • Third Law of Thermodynamics
  • Standard Entropies
  • Standard Entropies (298 K) from Absolute Entropies (0K)
  • Entropy Changes in the System
  • Slide 19
  • Thermodynamic Changes in Systems (Chem Reactions)
  • Entropy Changes in the Surroundings
  • Entropy Change in the Universe
  • Slide 23
  • Gibbs Free Energy (G)
  • Free Energy Changes
  • Spontaneity Enthalpy amp Entropy
  • Slide 27
  • Problems
  • Standard Free Energy Changes
  • Slide 30
  • Fourth Law of Thermodynamics Emergence
  • Slide 32
  • Slide 33
  • Slide 34
  • Slide 35
  • Slide 36
  • Slide 37
  • Slide 38
  • Slide 39
  • Slide 40
  • Slide 41
  • Slide 42
  • Slide 43
  • Slide 44
  • Slide 45
  • Slide 46
  • Slide 47
  • Slide 48
  • Slide 49
  • 2006 (B)
  • Slide 51
  • Slide 52
  • Slide 53
  • Slide 54
  • Slide 55
Page 49: Unit 14: Chemical Thermodynamics

ChemicalThermodynamics

ChemicalThermodynamics

2006 (B)

ChemicalThermodynamics

ChemicalThermodynamics

ChemicalThermodynamics

2007 (A)

ChemicalThermodynamics

ChemicalThermodynamics

  • Unit 14 Chemical Thermodynamics
  • First Law of Thermodynamics
  • Second Law of Thermodynamics
  • Spontaneous Processes
  • Slide 5
  • Spontaneity
  • Irreversible Processes
  • Entropy (S)
  • Slide 9
  • Second Law of Thermodynamics
  • Slide 11
  • Entropy on the Molecular Scale
  • Slide 13
  • Entropy Changes
  • Third Law of Thermodynamics
  • Standard Entropies
  • Standard Entropies (298 K) from Absolute Entropies (0K)
  • Entropy Changes in the System
  • Slide 19
  • Thermodynamic Changes in Systems (Chem Reactions)
  • Entropy Changes in the Surroundings
  • Entropy Change in the Universe
  • Slide 23
  • Gibbs Free Energy (G)
  • Free Energy Changes
  • Spontaneity Enthalpy amp Entropy
  • Slide 27
  • Problems
  • Standard Free Energy Changes
  • Slide 30
  • Fourth Law of Thermodynamics Emergence
  • Slide 32
  • Slide 33
  • Slide 34
  • Slide 35
  • Slide 36
  • Slide 37
  • Slide 38
  • Slide 39
  • Slide 40
  • Slide 41
  • Slide 42
  • Slide 43
  • Slide 44
  • Slide 45
  • Slide 46
  • Slide 47
  • Slide 48
  • Slide 49
  • 2006 (B)
  • Slide 51
  • Slide 52
  • Slide 53
  • Slide 54
  • Slide 55
Page 50: Unit 14: Chemical Thermodynamics

ChemicalThermodynamics

2006 (B)

ChemicalThermodynamics

ChemicalThermodynamics

ChemicalThermodynamics

2007 (A)

ChemicalThermodynamics

ChemicalThermodynamics

  • Unit 14 Chemical Thermodynamics
  • First Law of Thermodynamics
  • Second Law of Thermodynamics
  • Spontaneous Processes
  • Slide 5
  • Spontaneity
  • Irreversible Processes
  • Entropy (S)
  • Slide 9
  • Second Law of Thermodynamics
  • Slide 11
  • Entropy on the Molecular Scale
  • Slide 13
  • Entropy Changes
  • Third Law of Thermodynamics
  • Standard Entropies
  • Standard Entropies (298 K) from Absolute Entropies (0K)
  • Entropy Changes in the System
  • Slide 19
  • Thermodynamic Changes in Systems (Chem Reactions)
  • Entropy Changes in the Surroundings
  • Entropy Change in the Universe
  • Slide 23
  • Gibbs Free Energy (G)
  • Free Energy Changes
  • Spontaneity Enthalpy amp Entropy
  • Slide 27
  • Problems
  • Standard Free Energy Changes
  • Slide 30
  • Fourth Law of Thermodynamics Emergence
  • Slide 32
  • Slide 33
  • Slide 34
  • Slide 35
  • Slide 36
  • Slide 37
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  • 2006 (B)
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Page 51: Unit 14: Chemical Thermodynamics

ChemicalThermodynamics

ChemicalThermodynamics

ChemicalThermodynamics

2007 (A)

ChemicalThermodynamics

ChemicalThermodynamics

  • Unit 14 Chemical Thermodynamics
  • First Law of Thermodynamics
  • Second Law of Thermodynamics
  • Spontaneous Processes
  • Slide 5
  • Spontaneity
  • Irreversible Processes
  • Entropy (S)
  • Slide 9
  • Second Law of Thermodynamics
  • Slide 11
  • Entropy on the Molecular Scale
  • Slide 13
  • Entropy Changes
  • Third Law of Thermodynamics
  • Standard Entropies
  • Standard Entropies (298 K) from Absolute Entropies (0K)
  • Entropy Changes in the System
  • Slide 19
  • Thermodynamic Changes in Systems (Chem Reactions)
  • Entropy Changes in the Surroundings
  • Entropy Change in the Universe
  • Slide 23
  • Gibbs Free Energy (G)
  • Free Energy Changes
  • Spontaneity Enthalpy amp Entropy
  • Slide 27
  • Problems
  • Standard Free Energy Changes
  • Slide 30
  • Fourth Law of Thermodynamics Emergence
  • Slide 32
  • Slide 33
  • Slide 34
  • Slide 35
  • Slide 36
  • Slide 37
  • Slide 38
  • Slide 39
  • Slide 40
  • Slide 41
  • Slide 42
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  • 2006 (B)
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Page 52: Unit 14: Chemical Thermodynamics

ChemicalThermodynamics

ChemicalThermodynamics

2007 (A)

ChemicalThermodynamics

ChemicalThermodynamics

  • Unit 14 Chemical Thermodynamics
  • First Law of Thermodynamics
  • Second Law of Thermodynamics
  • Spontaneous Processes
  • Slide 5
  • Spontaneity
  • Irreversible Processes
  • Entropy (S)
  • Slide 9
  • Second Law of Thermodynamics
  • Slide 11
  • Entropy on the Molecular Scale
  • Slide 13
  • Entropy Changes
  • Third Law of Thermodynamics
  • Standard Entropies
  • Standard Entropies (298 K) from Absolute Entropies (0K)
  • Entropy Changes in the System
  • Slide 19
  • Thermodynamic Changes in Systems (Chem Reactions)
  • Entropy Changes in the Surroundings
  • Entropy Change in the Universe
  • Slide 23
  • Gibbs Free Energy (G)
  • Free Energy Changes
  • Spontaneity Enthalpy amp Entropy
  • Slide 27
  • Problems
  • Standard Free Energy Changes
  • Slide 30
  • Fourth Law of Thermodynamics Emergence
  • Slide 32
  • Slide 33
  • Slide 34
  • Slide 35
  • Slide 36
  • Slide 37
  • Slide 38
  • Slide 39
  • Slide 40
  • Slide 41
  • Slide 42
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  • Slide 48
  • Slide 49
  • 2006 (B)
  • Slide 51
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  • Slide 53
  • Slide 54
  • Slide 55
Page 53: Unit 14: Chemical Thermodynamics

ChemicalThermodynamics

2007 (A)

ChemicalThermodynamics

ChemicalThermodynamics

  • Unit 14 Chemical Thermodynamics
  • First Law of Thermodynamics
  • Second Law of Thermodynamics
  • Spontaneous Processes
  • Slide 5
  • Spontaneity
  • Irreversible Processes
  • Entropy (S)
  • Slide 9
  • Second Law of Thermodynamics
  • Slide 11
  • Entropy on the Molecular Scale
  • Slide 13
  • Entropy Changes
  • Third Law of Thermodynamics
  • Standard Entropies
  • Standard Entropies (298 K) from Absolute Entropies (0K)
  • Entropy Changes in the System
  • Slide 19
  • Thermodynamic Changes in Systems (Chem Reactions)
  • Entropy Changes in the Surroundings
  • Entropy Change in the Universe
  • Slide 23
  • Gibbs Free Energy (G)
  • Free Energy Changes
  • Spontaneity Enthalpy amp Entropy
  • Slide 27
  • Problems
  • Standard Free Energy Changes
  • Slide 30
  • Fourth Law of Thermodynamics Emergence
  • Slide 32
  • Slide 33
  • Slide 34
  • Slide 35
  • Slide 36
  • Slide 37
  • Slide 38
  • Slide 39
  • Slide 40
  • Slide 41
  • Slide 42
  • Slide 43
  • Slide 44
  • Slide 45
  • Slide 46
  • Slide 47
  • Slide 48
  • Slide 49
  • 2006 (B)
  • Slide 51
  • Slide 52
  • Slide 53
  • Slide 54
  • Slide 55
Page 54: Unit 14: Chemical Thermodynamics

ChemicalThermodynamics

ChemicalThermodynamics

  • Unit 14 Chemical Thermodynamics
  • First Law of Thermodynamics
  • Second Law of Thermodynamics
  • Spontaneous Processes
  • Slide 5
  • Spontaneity
  • Irreversible Processes
  • Entropy (S)
  • Slide 9
  • Second Law of Thermodynamics
  • Slide 11
  • Entropy on the Molecular Scale
  • Slide 13
  • Entropy Changes
  • Third Law of Thermodynamics
  • Standard Entropies
  • Standard Entropies (298 K) from Absolute Entropies (0K)
  • Entropy Changes in the System
  • Slide 19
  • Thermodynamic Changes in Systems (Chem Reactions)
  • Entropy Changes in the Surroundings
  • Entropy Change in the Universe
  • Slide 23
  • Gibbs Free Energy (G)
  • Free Energy Changes
  • Spontaneity Enthalpy amp Entropy
  • Slide 27
  • Problems
  • Standard Free Energy Changes
  • Slide 30
  • Fourth Law of Thermodynamics Emergence
  • Slide 32
  • Slide 33
  • Slide 34
  • Slide 35
  • Slide 36
  • Slide 37
  • Slide 38
  • Slide 39
  • Slide 40
  • Slide 41
  • Slide 42
  • Slide 43
  • Slide 44
  • Slide 45
  • Slide 46
  • Slide 47
  • Slide 48
  • Slide 49
  • 2006 (B)
  • Slide 51
  • Slide 52
  • Slide 53
  • Slide 54
  • Slide 55
Page 55: Unit 14: Chemical Thermodynamics

ChemicalThermodynamics

  • Unit 14 Chemical Thermodynamics
  • First Law of Thermodynamics
  • Second Law of Thermodynamics
  • Spontaneous Processes
  • Slide 5
  • Spontaneity
  • Irreversible Processes
  • Entropy (S)
  • Slide 9
  • Second Law of Thermodynamics
  • Slide 11
  • Entropy on the Molecular Scale
  • Slide 13
  • Entropy Changes
  • Third Law of Thermodynamics
  • Standard Entropies
  • Standard Entropies (298 K) from Absolute Entropies (0K)
  • Entropy Changes in the System
  • Slide 19
  • Thermodynamic Changes in Systems (Chem Reactions)
  • Entropy Changes in the Surroundings
  • Entropy Change in the Universe
  • Slide 23
  • Gibbs Free Energy (G)
  • Free Energy Changes
  • Spontaneity Enthalpy amp Entropy
  • Slide 27
  • Problems
  • Standard Free Energy Changes
  • Slide 30
  • Fourth Law of Thermodynamics Emergence
  • Slide 32
  • Slide 33
  • Slide 34
  • Slide 35
  • Slide 36
  • Slide 37
  • Slide 38
  • Slide 39
  • Slide 40
  • Slide 41
  • Slide 42
  • Slide 43
  • Slide 44
  • Slide 45
  • Slide 46
  • Slide 47
  • Slide 48
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  • 2006 (B)
  • Slide 51
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  • Slide 54
  • Slide 55

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