Lecture 6 Liquids and Solids.pptx

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Liquids and SolidsChapter 11

1



Liquids and Solids

2

~12 bar, assuming

gas is Ar, T=298K



Gases vs. Liquids &

Solids

3



Textbook Chapters to

Cover11.2 Solids, Liquids, and Gases: a Moleular

Co!parison

11.", 11.# $nter!oleular %ores11., 11.' (apori)ation, (apour *ressure,

Subli!ation and %usion

11.+ eatin- Curve or /ater

11.0 *hase ia-ra!s11. /ater: 3n 4xtraordinar5 Substane

11.11, 11.12 Cr5stalline Solids

4



4xluded Textbook

Chapters11.1 Cli!bin- Gekos and $nter!oleular

%ores

11.16 Cr5stalline Solids: eter!inin- TheirStruture b5 789a5 Cr5stallo-raph5

11.1" Cr5stalline Solids: and Theor5

5



;utline$nter!oleular %ores

*roperties o Liquids

*hase Chan-eseatin- Curves

*hase ia-ra!s

Cr5stalline Solids

6



IntermolecularForces%ores o attration & repulsion

;perative in !oleular solids, liquids, and -ases

<as opposed to !etalli, ovalent, & ioni solids=

7



%ores o attration &

repulsion%ores in non8!oleular solids: !etalli <e.-.

Cu=, ovalent <e.-. dia!ond=, and ioni <e.-.>aCl= bonds These ores are 16 ti!es stron-er than van der

/aals ores ?@ hi-h !p & bp.

%ores in !oleular speies: inter!oleular<aka van der /aals= oresA e.-.

2;, su-ar,

Baxdispersion ores <aka London ores=

dipole8dipole ores

h5dro-en bondin- 8

8



ispersion %ores3lso alled London %ores

;perate in all !oleules

ue to eletron loud <e..=Collision distorts e.. → instantaneous

dipole

$nst. dipole indues sa!e on nearb5!oleule

9



4et o Moleular Si)e

10

*olarisabilit5oB easil5 is eletron loud distortedD

More eletrons ? !ore polarisable



4et o Shape4xposed surae inreases interation

11



ipole8ipole

$nterationsetBeen !oleules Bith per!anent dipole

ipole results ro!

Enequal eletron sharin- <dierenteletrone-ativities=

3s5!!etr5 o !oleule

9elativel5 stron- inter!oleular ore

Stren-th depends on dipole !o!ent

12



4xa!ple: 8ClCl is ver5 eletrone-ativeA is less so

Cl pulls eletrons toBards its end <ne-ative=

let Bith partial positive har-e end o one Cl attrated to Cl end o

another

13



14

ipole8ipole $nterations



ipole Mo!ent &

S5!!etr51,2-Dichlorobenzene 1,4-Dichlorobenzene

Dipole moment2.6 deb5e <=

Boiling point1,28C: 106.FC

Dipole moment6.66 <s5!!etr5=

Boiling point1+#FC

15

>o net dipole



16

ipole Mo!ent & bp



LC: oilin- *oints/hih list o o!pounds is in order

o dereasin- boilin- pointD

3. $2, Cl2, r2

. C'', C''Cl, C''Cl2

C. 3s<C"=", *<C"=", ><C"="

. C#, C2', C"0

17



LC: oilin- *oints/hih list o o!pounds is in order

o dereasin- boilin- pointD

C. 3s<C"=", *<C"=", ><C"="

London ores operativeCo!pound Bith !ost eletrons Bill have

hi-hest b.p.

18



5dro-en ondin-Moleules Bith bound

to >, ;, or %.

ato! is eletropositive.SuperH dipole8dipole

ore, unusuall5 stron-.

>ot to be onused Bith a

he!ial bond <i.e. aovalent bond=.

19



20

5dro-en ondin-

Covalent

bond



21

5dro-en ondin-



LC: Choose the liquid at

9T;ne o these o!pounds is aliquid at 9T and the other tBo are

-ases. /hih one is a liquidD /h5D

3.2C?;

.C"%

C.2;2

22



LC: Choose the liquid at

9T;ne o these o!pounds is aliquid at 9T and the other tBo are

-ases. /hih one is a liquidD /h5D

C.2;2

3ll three have 1'810 e, i.e. si!ilar dispersionores. 3ll three have dipole !o!ents. ;nl52;2 has diretl5 bonded to an

eletrone-ative ato! <;=, i.e. h5dro-en

bondin-. 2;2 has the hi-hest bp. 23



$on8ipole %ores;perate in ionic solution. <More to o!e in Ch

12.=

24



4xa!ple/hih ores are operative in the olloBin-

substanesD oB do 5ou expet their b.p.Is too!pareD

Co!pound %ores:b.p.JFC

2;

C">2

>aCl

C"<C2=1#C"

Cl 25

8bondin-, London %ores

8bondin-, London %ores

$oni ondin-

London %ores

London %ores, dipole8dipole

London %ores

166

8'."

1#1"

1#

80

810"



26



Properties ofLiquids

27



*roperties o LiquidsSel8stud5: visosit5, surae tension, apillar5

ation <K11.#=

(apour *ressure

28



(apour *ressureVapour pressure is the equilibrium partial

pressure o the vapour in the spae above aliquid

29



(.*. inreases Bith te!p

30



(.*. inreases Bith te!p

31



(.*. inreases Bith te!p3 liquid Bill boil Bhen its vapour pressure

is equal to at!ospheri pressure.

The nor!al bp o a liquid is thete!perature at Bhih its vapour pressure is1.61"2 bar <1 at!=.

Liquids Bith hi-h vapour pressure at roo!

te!perature have loB boilin- points.

32



LC: oilin- /ater3 pot o Bater is plaed on a stove. eore itboils, bubbles or! at the botto! o the pot andrise to the top. /hat are the bubbles !ade oD

<3=eat

<=3ir

<C=;x5-en -as and h5dro-en -as

<=/ater vapour



bp at 266 !

(.*. inreases Bith

te!p(.*. urve an beused to nd boilin-point at pressuresother than 1.61"2bar <1 at! ? +'6

Torr=.

34

3t!os.press. at266 !

<"2 torr=



LC: (apour *ressure

The vapour pressure o aet5lene, C22,

stored in a pressuri)ed 5linder is about

6.62 bar at 16 and 2.6 bar at 266 ./hat is the !ost likel5 value or thevapour pressure at 1+ D

3. 6.62 bar

. 6." barC. 1.6 bar

. 1. bar

35



LC: (apour *ressure

. 6." bar

9e!e!ber shape o urve.

36

6.62

Te!p <=

16 266

2.66

1.66

1+

( a p p

r e s s < b a r =



Clausius8Clape5ron

4quation

4quation or the vapour pressure urve<T1,*1= and <T2,*2= are tBo vapour pressure

data

∆vap is the enthalp5 o vapourisation

9 is the -as onstant: 0."1# NJJ!ol>otes:

T is alBa5s in

∆

vap is in NJ!ol, so that units anel Bith 9

37

lnP2

P1

=∆Hvap

R

1

T1

− 1

T2



Eses or Clausius8

Clape5ron*redit (.*. at T2, -iven:

4nthalp5 o vapourisation <∆vap=

(.*. <*1= at te!perature T1

*redit boilin- point <T2= at pressure *2, -iven:

∆vap

>or!al bp <T1

, *1

=

;btain ∆vap -iven tBo T,* data

e.-. nor!al boilin- point and one other

38



4xa!ple/hat is the (.*. o Bater <in torr= at 6FC i it is10 torr at 2 FC <∆vap? ## kNJ!ol=D

3ns: rst, rearran-e C8C equation or *2

39

P2 = P1 exp

∆ H vap

R

1

T 1 −1

T 2



4xa!pleOont>ext, onvert te!peratures to & ∆vap to

NJ!ol:

T1 ? 20

T2 ? "2" ∆ ? ## 666 NJ!ol

*1 ? 10 torr

Then plu- in the values and alulate

*2 ? +1 torr

>ote: T inreased b5 0P, but * inreasedb5 26PQ

40



LC: Clausius8Clape5ron/hat is the bp o Bater at the Mexio Cit5airport <altitude 22"6 !A at!ospheri pressure? 00 torr=D

∆vap? #6.'0 kNJ!olA 9?0."1# N 81 !ol81A 1

at!?+'6 torr

3. 200.+

. "''.6

C. 2".'

. "06.'

41



LC: Clausius8Clape5ron. "''.6 <onl5 reasonable ansBer=

9earran-e C8C equation or 1JT1

9eall that T2,*2 is nor!al bp

42

21

2

vap1 T

1

P

PlnH

R

T

1 +∆

=

373.15

1

588

760ln

40680

8.3145

T

1

1

+=



Phase Chanes! Phase Diarams

43



*hase Chan-es

44



4nthalpies o Transition

45

∆Hvap° -∆Hvap°

∆Hfus°-∆Hfus°

∆Hsub° -∆Hsub°



46



eatin- Curves

47

q = mCs,steam

∆T

q = n∆vapH°

q = n∆fusH°q = mCs,liq∆T

q = mCs,ice∆T



*hase ia-ra!s

48

• Line segments (AC, AD, AB)

represent certain T & P at

which the substance is in

equilibrium between two

states.• Triple point (A) represents the

unique T and P at which solid,

liquid, and gaseous states are in

equilibrium.• Critical point (B) represents

the T & P above which a

supercritical fluid exists.



*hase ia-ra!s

49

Liquid will

not form

beyond this

temperature

(crit. temp.)

1 atm

bpmp



Critial Te!perature and *ressureCritical temperature:

above this te!perature, liquid state Bill notor!

Critical pressure: pressure required to lique5 -as at ritial

te!perature

3bove ritial T & *, Ruid is superritialH

50



Superritial en)ene

51



2; and C;2

52

Negative Slope (atypical) Positive Slope (typical)



Solids" Propertiesand #ondin

53



;rder in Solids TBo t5pes

Crystalline: ato!s in

ordered !atrixe.-. quart)

solids have aets, leave alon- Bell denedplanes

Amorphous: short8ran-e ordersolids !elt over ran-e o te!peratures

properties depend on preparation

54



55



Moleular Solidsvan der /aals interations

e.-. 3r<s=, 2;<s=, C'12;'<s=

loB bp & !peletrial insulators

soluble in solvents o si!ilar polarit5

56



Moleular Solids

Boiling point depends onnu!ber o eletrons, as expeted

Melting point depends onstren-th o inter!oleular ores

eien5 o pakin- <!oleular shape=

57

CH3Benzene:

mp = 5˚C

bp = 80˚C

Toluene:

mp = -95˚C

bp = 111˚C



$oni Solidse.-. >aCl <s=, CsCl <s=, nS <s=, Ca%2 <s=

ondin-: eletrostati attration betBeen ions

ard, brittle

i-h !p & bpbp & !p depend on surface charge density o

ions

!p o M-; ? 202°CA !p o >aCl ? 061°C4letrial and ther!al insulators

So!e are soluble in polar solvents

58



Metalli Solidse.-. %e<s=, >a<s=

ondin-: Metal ions in a seaH o valeneeletrons

Sot, dutile, !alleable

(ariable !p & bpMo !p 2'2" °CA >a !p 0 °CA - !p 8" °C

Man5 are soluble in <reat Bith= aids4letrial and ther!al ondutors

59



>etBork Covalent Solidse.-. C<dia!ond=, C<-raphite=, SiC<s=

Covalent bondin-: ato!s share eletrons

(er5 hard & brittle(er5 hi-h bp & !p

$nsulators or se!iondutorsC<-raphite= is ondutor

$nsoluble in solvents

60



>etBork Covalent Solids

61

Van der Waals

Forces

Covalent bonds



LC: !eltin- points/hih solid has the loBest !eltin- point andBh5D

3. >aCl<s=

. C<s, dia!ond=

C. C"1'#<s=

62



LC: !eltin- points/hih solid has the loBest !eltin- point andBh5D

3. >aCl<s=

. C<s, dia!ond=

C. C"1'#<s=

C"1'# is a !oleular solid held to-ether b5 van

der /aals <inter!oleular= ores.>aClJdia!ond is held to-ether b5

ioniJovalent bonds, respetivel5, ten ti!es63



Cr$stal Structure

in Solids

64



Cr5stal Struture TBo parts to a r5stal

Lattice9epeatin- "8 pattern o points in spae

Theoretial

BasisChe!ial unit <ato!, !oleule, et.=

;ne basis unit at eah lattie point

65

C t l L tti d E it



Cr5stal Lattie and Enit

CellLattie o!prised o repeatin- units alledunit ells

66



Cubi Enit Cells

67

e.-. poloniu!*o<s=

e.-. alpha ironα8%e<s=

e.-. platinu!*t<s=

> b t it



>u!ber o ato!s per unit

ell

68

8×1 / 8 = 1 atom 8×1 / 8 + 1 = 2 atoms 8×1 / 8 + 6×1 / 2= 4 atoms

Si!ple Cubi od5 Centred Cubi %ae Centred Cubi



LC: %ind the %or!ula%ro! the unit ell, beloB, Bhat is the or!ula o

the oxide o niobiu!D

A. NbO

B. NbO2

C. Nb2O3

D. Nb2O

69



%ind the %or!ula3. >b;12 O atoms shown

4ah has U insideell

Thereore, " ; ato!s6 Nb atoms shown

4ah has V insideell

Thereore, " >bato!s

Formula: Nb3O3

S!allest ratio: >b;

70

S tili ti i bi



Spae utilisation in ubi

ells

71

Si!ple Cubi<1 ato!=

od5 Centred Cubi<2 ato!s=

%ae Centred Cubi<# ato!s=

# r 2 r# r

a

%&'2r()&*r) <#r=2 ?a2Wa2Wa2

a ? r√<1'J"=% &

<#r=2 ? a2Wa2

a ? r√0

% & r)

'*()2

S tili ti i bi



Spae utilisation in ubi

ellsoB !uh spae taken up b5 ato!sD

3to! volu!e ? <#J"=πr"

Si!ple ubi:1 ato! per ell: <#J"=πr"J<0r"= ? πJ' ? 2./0

od58entred ubi:

2 ato!s per ell: 2×<#J"=πr"J<r"<1'J"="J2= ? +*.0

%ae8entered ubi: do the alulation5ourselQ

72



LC: spae utilisationoB !uh spae istaken up b5 ato!s<as a perenta-e= in a

ae8entred ubiD

73 73

%ae Centred Cubi



LC: spae utilisationoB !uh spae istaken up b5 ato!s ina ae8entred ubiD

# ato!s per ell:

#×<#J"=πr" J<r"<0="J2=

? /.0

74 74

%ae Centred Cubi



M5 Super *oBer$ 5ou ould have an5 super poBer, BhatBould it beD

75

Packing the most amount

of stuff into the smallest

amount of space/time!

Close packing maximizes

atomic interactions and

minimizes the volume



LC: %ind the densit5(anadiu! <(= r5stallises in a b struture and

has an ato!i radius o 1"1 p!. eter!ine thedensit5 i the ed-e len-th o the b unit ell is

#rJ√" and the ato!i !ass is 6.# -J!ol. <>3 ? '.622×162" !ol81=

3. ".6' -J!"

. '.11 -J!"

C. 2.++ -J!"

. 12.2 -J!"

4. 0.#' -J!"

76



LC: %ind the densit5. '.11 -J!"

.Enit ell vol. ? X#×<1"1×16816 !=J√"Y" ?2.+'0×1682" !"

.2 ato!sJell: 2J<'.622×162" !ol81= ?"."21×1682# !ol

.

densit5: <"."21×1682# !ol=<6.# -J!ol=J<2.++×1682" !"=

.densit5: '.11 -J!"

77



Su!!ar5Solids and liquids lassied b5 ores oattration

*roperties o substane result ro! ores o

attration!.p., b.p., ondutivit5, visosit5, et.

*hase han-e data su!!arised b5 heatingcurves & phase diagrams

Cr5stal struture o solids lassied b5 crystallattice and the basis

Moleular or!ula an be ound ro! the unit

ell 78

Su--ested Ch 11



Su--ested Ch 11

4xerises9evieB questions 28#.

*roble!s b5 Topi, Cu!ulative *roble!s,Challen-e *roble!s: #, ", , , '1, '",

'+, ', +", ++, +, 0", 0, 0+, 0, 1, +, ,161, 16, 16+, 111, 11", 12, 1#1, 1, 1'1.

>ote: ansBers to all odd8nu!bered proble!sare ound in 3ppendix $$$.

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Lecture 6 Liquids and Solids.pptx