Chapter 13 “States of Matter” Pre-AP Chemistry Charles Page High School Stephen L. Cotton

Chapter 13Chapter 13“States of Matter”“States of Matter”

Pre-AP ChemistryPre-AP ChemistryCharles Page High SchoolCharles Page High School

Stephen L. CottonStephen L. Cotton

Bellringer #25 (Apr 5Bellringer #25 (Apr 5thth, , 2011)2011)

What is KINETIC energy? What is KINETIC energy? How is kinetic energy How is kinetic energy different from POTENTIAL different from POTENTIAL energy?energy?

Mini Quiz 13.1Mini Quiz 13.1

Answer the questions below on a Answer the questions below on a looseleaf sheet of paper using your looseleaf sheet of paper using your worksheet from yesterday.worksheet from yesterday.

When does a When does a vacuumvacuum exist? exist? How does How does atmospheric pressureatmospheric pressure result? result? How does atmospheric pressure How does atmospheric pressure

decrease?decrease? When could particles of all substances When could particles of all substances

stop moving?stop moving?

Agenda (Apr 5Agenda (Apr 5thth, 2011), 2011)

Bellringer #25Bellringer #25 Homework Check/Homework Homework Check/Homework

CollectionCollection 13.1 Objectives13.1 Objectives Review Section 13.1Review Section 13.1 Homework: Cornell Notes 13.2Homework: Cornell Notes 13.2

Section 13.1Section 13.1The Nature of GasesThe Nature of Gases

OBJECTIVES:OBJECTIVES:

DescribeDescribe the assumptions the assumptions of the “kinetic theory” as it of the “kinetic theory” as it applies to gases.applies to gases.



InterpretInterpret gas pressure in gas pressure in terms of kinetic theory.terms of kinetic theory.



DefineDefine the relationship the relationship between Kelvin temperature between Kelvin temperature and average kinetic energy.and average kinetic energy.


KineticKinetic refers to motion refers to motionPotential Potential energy refers to an object energy refers to an object

ABOUT to moveABOUT to move The energy an object has because of The energy an object has because of

it’s motion is called it’s motion is called kinetic energykinetic energy The The kinetic theorykinetic theory states that the tiny states that the tiny

particles in particles in all forms of matterall forms of matter are in are in constant motionconstant motion!!

Section 13.1Section 13.1The Nature of Gases (Kinetic The Nature of Gases (Kinetic

Theory)Theory) Three basic assumptionsThree basic assumptions of the kinetic of the kinetic

theory as it applies to gases:theory as it applies to gases: #1#1. Gas is . Gas is composed of particlescomposed of particles--

usually molecules or atomsusually molecules or atoms Small, hard spheresSmall, hard spheres Insignificant volume; relatively far Insignificant volume; relatively far

apart from each otherapart from each other No attraction or repulsion between No attraction or repulsion between

particlesparticles


Theory)Theory) #2#2. Particles in a gas move rapidly . Particles in a gas move rapidly

in in constant constant randomrandom motion motion Move in straight paths, changing Move in straight paths, changing

direction only when colliding with one direction only when colliding with one another or other objectsanother or other objects

Average speed of OAverage speed of O22 in air at 20 in air at 20 ooC is C is

an amazing 1700 km/h!an amazing 1700 km/h!

- Page 385 Top


Theory)Theory)

#3#3. Collisions are . Collisions are perfectly perfectly elasticelastic-- meaning kinetic energy meaning kinetic energy is transferred without loss from is transferred without loss from one particle to another- the total one particle to another- the total kinetic energy remains constantkinetic energy remains constant


Gas PressureGas Pressure – defined as the force – defined as the force exerted by a gas per unit surface exerted by a gas per unit surface area of an objectarea of an object Due to: a) Due to: a) force of collisionsforce of collisions, and b) , and b)

number of collisionsnumber of collisions No particles present? Then there No particles present? Then there

cannot be any collisions, and thus no cannot be any collisions, and thus no pressure – called a pressure – called a vacuumvacuum


Atmospheric pressureAtmospheric pressure results from results from the collisions of air molecules with the collisions of air molecules with objectsobjects Decreases as you climb a mountain Decreases as you climb a mountain

because the air layer thins out as because the air layer thins out as elevation increaseselevation increases

BarometerBarometer is the measuring device is the measuring device for atmospheric pressure, which is for atmospheric pressure, which is dependent upon weather & altitudedependent upon weather & altitude

Measuring PressureMeasuring Pressure

The first device for measuring atmosphericpressure was developed by Evangelista Torricelli during the 17th century.

The device was called a “barometer”

Baro = weight Meter = measure Torricelli


The SI unit of pressure is the The SI unit of pressure is the pascal pascal (Pa)(Pa) At sea level, atmospheric pressure is At sea level, atmospheric pressure is

about 101.3 about 101.3 kilopascalskilopascals (kPa) (kPa) Older units of pressure include millimeters Older units of pressure include millimeters

of mercury (mm Hg), and atmospheres of mercury (mm Hg), and atmospheres (atm) – both of which came from using a (atm) – both of which came from using a mercury barometermercury barometer

You WILL see atmospheres (atm) again in You WILL see atmospheres (atm) again in a later unita later unit


Mercury BarometerMercury Barometer – Fig. 13.2, – Fig. 13.2, page 386 – a straight glass tube page 386 – a straight glass tube filled with Hg, and closed at one filled with Hg, and closed at one end; placed in a dish of Hg, with the end; placed in a dish of Hg, with the open end below the surfaceopen end below the surface At sea level, the mercury would rise to At sea level, the mercury would rise to

760 mm high at 25 760 mm high at 25 ooC- called one C- called one standard atmospherestandard atmosphere (atm) (atm)

An Early An Early BarometerBarometer

The normal pressure due to the atmosphere at sea level can support a column of mercury that is 760 mm high.


For gases, it is important to relate For gases, it is important to relate measured values to standardsmeasured values to standards Standard values are defined as a Standard values are defined as a

temperature of 0temperature of 0 o oC and a pressure of C and a pressure of 101.3 kPa, or 1 atm101.3 kPa, or 1 atm

This is called This is called Standard Standard Temperature and PressureTemperature and Pressure, or , or STPSTP


What happens when a substance is What happens when a substance is heated? Particles absorb energy!heated? Particles absorb energy! Some of the energy is storedSome of the energy is stored within within

the particles- this is potential energy, the particles- this is potential energy, and does not raise the temperatureand does not raise the temperature

Remaining energy speeds up the Remaining energy speeds up the particles (increases average kinetic particles (increases average kinetic energy)- thus energy)- thus increases temperatureincreases temperature


The particles in any collection have The particles in any collection have a wide range of kinetic energies, a wide range of kinetic energies, from very low to very high- but most from very low to very high- but most are somewhere in the middle, thus are somewhere in the middle, thus the term the term averageaverage kinetic energy kinetic energy is is usedused The higher the temperature, the wider The higher the temperature, the wider

the range of kinetic energiesthe range of kinetic energies


An increase in the average kinetic An increase in the average kinetic energy of particles causes the energy of particles causes the temperature to rise.temperature to rise. As it cools, the particles tend to move As it cools, the particles tend to move

more slowly, and the average K.E. more slowly, and the average K.E. declines.declines.

Is there a point where they slow down Is there a point where they slow down

enough to enough to stopstop moving? moving?


The particles would have no kinetic The particles would have no kinetic energy at that point, because they energy at that point, because they would have no motionwould have no motion Absolute zeroAbsolute zero (0 K, or –273 (0 K, or –273 ooC) is C) is

the temperature at which the motion the temperature at which the motion of particles of particles theoretically ceasestheoretically ceases

This has never been reached, but This has never been reached, but about 0.5 x 10about 0.5 x 10-9-9 K has been achieved K has been achieved


The Kelvin temperature scale The Kelvin temperature scale reflects a reflects a direct relationshipdirect relationship between temperature and average between temperature and average kinetic energykinetic energyParticles of He gas at 200 K have Particles of He gas at 200 K have

twice the average kinetic energytwice the average kinetic energy as particles of He gas at 100 Kas particles of He gas at 100 K


Solids and liquids differ in their Solids and liquids differ in their response to temperatureresponse to temperature However, at any given temperature the However, at any given temperature the

particles of all substances, regardless of particles of all substances, regardless of their physical state, have the same their physical state, have the same average kinetic energyaverage kinetic energy

What happens to the temperature of a What happens to the temperature of a substance when the average kinetic substance when the average kinetic energy of its particles decreases?energy of its particles decreases?


How does pressure occur? How does pressure occur? Name something that can Name something that can

INCREASE pressure?INCREASE pressure?


How would you compare the How would you compare the INTERMOLECULAR attractions of a INTERMOLECULAR attractions of a liquid to the INTERMOLECULAR liquid to the INTERMOLECULAR attractions of a gas?attractions of a gas?


Bellringer #27Bellringer #27 13.2 Cornell Note Check13.2 Cornell Note Check Write 13.2 ObjectivesWrite 13.2 Objectives Discuss 13.2: The Nature of LiquidsDiscuss 13.2: The Nature of Liquids Homework: 13.3 Cornell NotesHomework: 13.3 Cornell Notes

Section 13.2Section 13.2The Nature of LiquidsThe Nature of Liquids


IdentifyIdentify factors that factors that determine physical properties determine physical properties of a liquid.of a liquid.



DefineDefine “evaporation” in “evaporation” in terms of kinetic energy.terms of kinetic energy.



DescribeDescribe the equilibrium the equilibrium between a liquid and its between a liquid and its vapor.vapor.



IdentifyIdentify the conditions at the conditions at which boiling occurs.which boiling occurs.


Liquid particlesLiquid particles are also in motion. are also in motion.Liquid particles are free to Liquid particles are free to slide slide

pastpast one another one anotherGases and liquids can both Gases and liquids can both

FLOW, as seen in Fig. 13.5, p.390FLOW, as seen in Fig. 13.5, p.390However, liquid particles However, liquid particles are are

attractedattracted to each other, whereas to each other, whereas gases are notgases are not


Particles of a liquid spin and vibrate Particles of a liquid spin and vibrate while they move, thus contributing while they move, thus contributing to their average kinetic energyto their average kinetic energy But, most of the particles But, most of the particles do notdo not have have

enough energy to escape into the enough energy to escape into the gaseous state; they would gaseous state; they would have to have to overcomeovercome their intermolecular their intermolecular attractions with other particlesattractions with other particles


The intermolecular attractions also The intermolecular attractions also reduce the amount of space between reduce the amount of space between particles of a liquidparticles of a liquidThus, liquids are more Thus, liquids are more densedense than than

gasesgases Increasing pressure on liquid has Increasing pressure on liquid has

hardly any effecthardly any effect on it’s on it’s volumevolume


Increasing the pressure also has Increasing the pressure also has little effect on the little effect on the volume of a volume of a solidsolid For that reason, liquids and solids are For that reason, liquids and solids are

known as the known as the condensed states of condensed states of mattermatter


The conversion of a liquid to a gas or The conversion of a liquid to a gas or vapor is called vapor is called vaporizationvaporization When this occurs at the When this occurs at the surfacesurface of a liquid of a liquid

that is that is notnot boiling, the process is called boiling, the process is called evaporationevaporation

Some of the particles break away and Some of the particles break away and enter the gas or vapor state; but enter the gas or vapor state; but onlyonly those those with the minimum kinetic energy needed to with the minimum kinetic energy needed to move into the gaseous statemove into the gaseous state


A liquid will also evaporate faster when A liquid will also evaporate faster when heatedheated Because the added heat increases the Because the added heat increases the

average kinetic energy needed to average kinetic energy needed to overcome the attractive forcesovercome the attractive forces

But, evaporation is a But, evaporation is a cooling processcooling process Cooling occurs because those with the Cooling occurs because those with the

highest energy escape first (the highest energy escape first (the warmest molecules)warmest molecules)


Particles left behind have Particles left behind have lowerlower average kinetic energies; thus the average kinetic energies; thus the temperature decreasestemperature decreases Similar to removing the fastest runner Similar to removing the fastest runner

from a race- the remaining runners from a race- the remaining runners have a lower average speedhave a lower average speed

Evaporation helps to keep our skin Evaporation helps to keep our skin cooler on a hot day. Why?cooler on a hot day. Why?


Evaporation of a liquid in a closed Evaporation of a liquid in a closed container is somewhat differentcontainer is somewhat different Fig. 13.6b on page 391 shows that no Fig. 13.6b on page 391 shows that no

particles can escape into the outside particles can escape into the outside airair

When some particles do vaporize, When some particles do vaporize, these collide with the walls of the these collide with the walls of the container producing container producing vapor pressure vapor pressure (think of a tea kettle)(think of a tea kettle)


Eventually, some of the particles will Eventually, some of the particles will return to the liquid, or return to the liquid, or condensecondense

After a while, the number of After a while, the number of particles evaporating will equal the particles evaporating will equal the number condensing- the space number condensing- the space above the liquid is now saturated above the liquid is now saturated with vaporwith vapor A dynamic equilibrium existsA dynamic equilibrium exists Rate of evaporationRate of evaporation = = rate of condensationrate of condensation


We now know the rate of We now know the rate of evaporation from an open container evaporation from an open container increases as heat is addedincreases as heat is added The heating allows larger numbers of The heating allows larger numbers of

particles at the liquid’s surface to particles at the liquid’s surface to overcome the attractive forcesovercome the attractive forces

Heating allows the average kinetic Heating allows the average kinetic energy of all particles to increaseenergy of all particles to increase


The The boiling pointboiling point (bp) is the (bp) is the temperature at which the temperature at which the vapor vapor pressure of the liquid is just equal to pressure of the liquid is just equal to the external pressure on the liquidthe external pressure on the liquidBubbles form Bubbles form throughoutthroughout the the

liquid, rise to the surface, and liquid, rise to the surface, and escape into the airescape into the air


Since the boiling point is where the Since the boiling point is where the vapor pressure equals external vapor pressure equals external pressure, the bp changes if the pressure, the bp changes if the external pressure changesexternal pressure changes

Normal boiling pointNormal boiling point-- defined as defined as the bp of a liquid at a pressure of the bp of a liquid at a pressure of 101.3 kPa (or standard pressure)101.3 kPa (or standard pressure)


Normal bp of water = 100 Normal bp of water = 100 ooCC However, in Denver = 95 However, in Denver = 95 ooC, since C, since

Denver is 1600 m above sea level and Denver is 1600 m above sea level and average atmospheric pressure is about average atmospheric pressure is about 85.3 kPa (Recipe adjustments?)85.3 kPa (Recipe adjustments?)

In In pressure cookerspressure cookers, which reduce , which reduce cooking time, water boils cooking time, water boils aboveabove 100 100 ooC C due to the increased pressuredue to the increased pressure


Turning down the source of external Turning down the source of external heat drops the liquid’s temperature heat drops the liquid’s temperature below the boiling pointbelow the boiling point

Supplying more heat allows Supplying more heat allows particles to acquire enough KE to particles to acquire enough KE to escape- the escape- the temperature does not temperature does not go above the boiling pointgo above the boiling point, the liquid , the liquid only boils at a faster rateonly boils at a faster rate

- Page 394

Questions:

a. 60 oC b. about 20 kPa c. about 30 kPa


Rank in INCREASING order the Rank in INCREASING order the INTERMOLECULAR FORCES of INTERMOLECULAR FORCES of solids, liquids, and gases.solids, liquids, and gases.

Rank in INCREASING ORDER the Rank in INCREASING ORDER the kinetic energy of solids, liquids, and kinetic energy of solids, liquids, and gases.gases.


Bellringer #28Bellringer #28 Cornell Notes Check 13.3Cornell Notes Check 13.3 Write 13.3 ObjectivesWrite 13.3 Objectives Review 13.3Review 13.3 Pg. 399 #17-20; pg. 407 #45-47; Pg. 399 #17-20; pg. 407 #45-47;

AND 13.4 Cornell NotesAND 13.4 Cornell Notes

Section 13.3Section 13.3The Nature of SolidsThe Nature of Solids


EvaluateEvaluate how the way how the way particles are organized particles are organized explains the properties of explains the properties of solids.solids.



IdentifyIdentify the factors that the factors that determine the shape of a determine the shape of a crystal.crystal.



ExplainExplain how allotropes of an how allotropes of an element are different.element are different.


Particles in a liquid are relatively Particles in a liquid are relatively free to movefree to moveSolid particles are Solid particles are notnot

Figure 13.10, page 396 shows Figure 13.10, page 396 shows solid particles tend to solid particles tend to vibratevibrate about fixed pointsabout fixed points, rather than , rather than sliding from place to placesliding from place to place


Most solids have particles packed Most solids have particles packed against one another in a highly against one another in a highly organized patternorganized pattern Tend to be dense and incompressibleTend to be dense and incompressible Do not flow, nor take the shape of Do not flow, nor take the shape of

their containertheir container Are still able to move, unless they Are still able to move, unless they

would reach absolute zerowould reach absolute zero


When a solid is heated, the particles When a solid is heated, the particles vibrate more rapidly as the kinetic vibrate more rapidly as the kinetic energy increasesenergy increases The organization of particles within The organization of particles within

the solid breaks down, and eventually the solid breaks down, and eventually the solid meltsthe solid melts

The The melting pointmelting point (mp) is the (mp) is the temperature a solid turns to liquidtemperature a solid turns to liquid


At the melting point, the disruptive At the melting point, the disruptive vibrations are strong enough to vibrations are strong enough to overcome the interactions holding overcome the interactions holding them in a fixed positionthem in a fixed position Melting point can be reversed by Melting point can be reversed by

cooling the liquid so it cooling the liquid so it freezesfreezes Solid liquidSolid liquid


Generally, Generally, most ionic solids have most ionic solids have high melting pointshigh melting points, due to the , due to the relatively strong forces holding them relatively strong forces holding them togethertogether Sodium chloride (an ionic compound) Sodium chloride (an ionic compound)

has a melting point = 801 has a melting point = 801 ooCC Molecular compounds have Molecular compounds have

relatively low melting pointsrelatively low melting points


Hydrogen chloride (a molecular Hydrogen chloride (a molecular compound) has a mp = -112 compound) has a mp = -112 ooCC

Not all solids melt- wood and cane Not all solids melt- wood and cane sugar tend to decompose when sugar tend to decompose when heatedheated

Most solid substances are Most solid substances are crystallinecrystalline in structure in structure


In a In a crystalcrystal, such as Fig. 13.10, , such as Fig. 13.10, page 396, the particles (atoms, page 396, the particles (atoms, ions, or molecules) are arranged in ions, or molecules) are arranged in a orderly, repeating, three-a orderly, repeating, three-dimensional pattern called a dimensional pattern called a crystal crystal latticelattice

All crystals have a regular shape, All crystals have a regular shape, which reflects their arrangementwhich reflects their arrangement


The shape of a crystal depends The shape of a crystal depends upon the arrangement of the upon the arrangement of the particles within itparticles within itThe smallest group of particles The smallest group of particles

within a crystal that retains the within a crystal that retains the geometric shape of the crystal is geometric shape of the crystal is known as a known as a unit cellunit cell


There are three kinds of unit There are three kinds of unit cells that can make up a cubic cells that can make up a cubic crystal system:crystal system:1. Simple cubic1. Simple cubic2. Body-centered cubic2. Body-centered cubic3. Face-centered cubic3. Face-centered cubic

90o angle

- Page 398


Some solid substances can exist in Some solid substances can exist in more than onemore than one form form Elemental carbon is an example, as Elemental carbon is an example, as

shown in Fig. 13.13, page 399shown in Fig. 13.13, page 399 1. 1. DiamondDiamond, formed by great pressure, formed by great pressure 2. 2. GraphiteGraphite, which is in your pencil, which is in your pencil 3. 3. BuckminsterfullereneBuckminsterfullerene (also called (also called

“buckyballs”) arranged in hollow “buckyballs”) arranged in hollow cages like a soccer ballcages like a soccer ball


These are called These are called allotropesallotropes of of carbon, because all are made of carbon, because all are made of pure carbon only , and all are solidpure carbon only , and all are solid

AllotropesAllotropes are two or more different are two or more different molecular forms of the same molecular forms of the same element in the same physical stateelement in the same physical state

Not all solids are crystalline, but Not all solids are crystalline, but instead are instead are amorphousamorphous


AmorphousAmorphous solids lack an ordered solids lack an ordered internal structureinternal structure Rubber, plastic, and asphalt are all Rubber, plastic, and asphalt are all

amorphous solids- their atoms are amorphous solids- their atoms are randomly arrangedrandomly arranged

Another example is glass- Another example is glass- substances cooled to a rigid state substances cooled to a rigid state without crystallizingwithout crystallizing


Glasses are sometimes called Glasses are sometimes called supercooled liquidssupercooled liquids The irregular internal structures of The irregular internal structures of

glasses are intermediate between glasses are intermediate between those of a crystalline solid and a free-those of a crystalline solid and a free-flowing liquidflowing liquid

Do not melt at a definite mp, but Do not melt at a definite mp, but gradually soften when heatedgradually soften when heated


When a crystalline solid is When a crystalline solid is shattered, the fragments tend to shattered, the fragments tend to have the same surface angles as have the same surface angles as the original solidthe original solid

By contrast, when amorphous solids By contrast, when amorphous solids such as glass is shattered, the such as glass is shattered, the fragments have irregular angles and fragments have irregular angles and jagged edgesjagged edges

Summary ChartSummary Chart

State State of of MatteMatterr

ArrangemeArrangementnt

MotionMotion IntermoleculIntermolecular Forcesar Forces

Kinetic Kinetic EnergyEnergy

Solid Solid Very Close Very Close Particles, Particles, No Space No Space BetweenBetween

Only Only VibratVibratee

HighHigh LowLow

LiquidLiquid Some space Some space between between particlesparticles

Slide, Slide, VibratVibrate, Spine, Spin

MiddleMiddle MiddleMiddle

GasGas Mostly Mostly space space between between particlesparticles

RandoRandomm

NoneNone HighHigh

Bellringer #29Bellringer #29

What happens to the particles in a What happens to the particles in a solid when they get heated? What solid when they get heated? What happens to the particles in a liquid happens to the particles in a liquid when they get heated?when they get heated?

AgendaAgenda

Bellringer #29Bellringer #29 Homework Collection/Homework Homework Collection/Homework

CheckCheck Review 13.4Review 13.4 Unit 13 Review SheetUnit 13 Review Sheet Test FRIDAY!!!!Test FRIDAY!!!!

Section 13.4Section 13.4Changes of StateChanges of State


IdentifyIdentify the conditions the conditions necessary for sublimation.necessary for sublimation.



DescribeDescribe how equilibrium how equilibrium conditions are represented conditions are represented in a phase diagram.in a phase diagram.



Identify Identify if a state change is if a state change is endothermic or exothermic.endothermic or exothermic.



IdentifyIdentify the sections in a the sections in a heating/cooling curve.heating/cooling curve.


SublimationSublimation- the change of a - the change of a substance from a solid directly to substance from a solid directly to a vapor, without passing through a vapor, without passing through the liquid statethe liquid stateExamples: iodine (Fig. 13.14, p. Examples: iodine (Fig. 13.14, p.

401); dry ice (-78 401); dry ice (-78 ooC); mothballs; C); mothballs; solid air freshenerssolid air fresheners


Sublimation is useful in situations such Sublimation is useful in situations such as as freeze-dryingfreeze-drying foods- such as by foods- such as by freezing the freshly brewed coffee, and freezing the freshly brewed coffee, and then removing the water vapor by a then removing the water vapor by a vacuum pumpvacuum pump

Also useful in separating substances - Also useful in separating substances - organic chemists use it separate organic chemists use it separate mixtures and purify materialsmixtures and purify materials


The relationship among the solid, The relationship among the solid, liquid, and vapor states (or phases) liquid, and vapor states (or phases) of a substance in a sealed container of a substance in a sealed container are best represented in a single are best represented in a single graph called a graph called a phase diagramphase diagram

Phase diagramPhase diagram- gives the temperature - gives the temperature and pressure at which a substances and pressure at which a substances exists as solid, liquid, or gas (vapor)exists as solid, liquid, or gas (vapor)


Fig. 13.15, page 403 shows the Fig. 13.15, page 403 shows the phase diagram for waterphase diagram for water Each region represents a pure phaseEach region represents a pure phase Line between regions is where the Line between regions is where the

two phases exist in two phases exist in equilibriumequilibriumTriple pointTriple point is where all 3 curves is where all 3 curves

meet, the conditions where all 3 meet, the conditions where all 3 phases exist in equilibrium!phases exist in equilibrium!

Phase changes by Name

Critical Point

Temperature (oC)

Pre

ssu

re (

kPa)

- Page 403

Questions:

Exothermic vs. Exothermic vs. EndothermicEndothermic

When state changes occur a When state changes occur a substance is either ABSORBING or substance is either ABSORBING or RELEASING heat.RELEASING heat. Exothermic: when a Exothermic: when a

substance/reaction RELEASES heat substance/reaction RELEASES heat (ex: when liquid water freezes)(ex: when liquid water freezes)

Endothermic: when a Endothermic: when a substance/reaction ABSORBS heat substance/reaction ABSORBS heat (ex: when ice melts)(ex: when ice melts)

Endothermic or Endothermic or Exothermic?Exothermic?

1) Taking Ice Cream Out the Freezer1) Taking Ice Cream Out the Freezer

2) Lighting a Match2) Lighting a Match

3) Morning Dew Forming on Grass3) Morning Dew Forming on Grass

4) Boiling water4) Boiling water

Heating Curve (shows Heating Curve (shows ENDOTHERMIC changes)ENDOTHERMIC changes)


You take a glass of water outside on You take a glass of water outside on a HOT summer day. Someone calls a HOT summer day. Someone calls you inside for awhile and you leave you inside for awhile and you leave your glass of ice water outside. What your glass of ice water outside. What types of phase changes have taken types of phase changes have taken place with the glass of ice water? place with the glass of ice water? State if these changes are State if these changes are EXOTHERMIC or ENDOTHERMIC.EXOTHERMIC or ENDOTHERMIC.


Bellringer #30Bellringer #30 Questions about Review SheetQuestions about Review Sheet Continue Working on Review SheetContinue Working on Review Sheet Extra Credit Option: pg.408 #50, 51, Extra Credit Option: pg.408 #50, 51,

52, 55, 56, 57, 58, 59, 63, 6552, 55, 56, 57, 58, 59, 63, 65

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Chapter 13 “States of Matter” Pre-AP Chemistry Charles Page High School Stephen L. Cotton