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_ Copyright © Glencoe/McGraw-Hill, a division of The McGraw-Hill Companies, Inc. L 2 _ 8 8 9 4 0 at10°C. moving fasterandhavemorekineticenergythanwater kinetic energy. Forexample,watermoleculesat25°Care moving atgreaterspeeds.Therefore,theparticleshavemore meansthattheparticles,onaverage,are inanobject. edn setas ttso atr States ofMatter Reading Essentials Kinetic Energy Kinetic andPotential Energy Changes inState States ofMatter energy ofparticlesagivensubstance. gaseous statemovequickly. Theyhavethemostkinetic Therefore, theyhavemorekineticenergy. Particlesinthe the liquidstatemovefasterthanparticlesinsolidstate. energy. Thisisbecausetheyonlyvibrateinplace.Particles particles inthesolidstatehaveleastamountofkinetic energy theyhave.Within agivensubstance,suchaswater, has duetoitsmotion. moving. Theseparticleshave , agas.Whatcausesparticlestochangestate? , andtheairabovesnowicecontainswater arepresent.Thesnowisasolid,themelted 8 this lesson,reread thestatements to seeifyou have changedyour mind. if you agree withthestatement oraDifyou disagree. After you’ve read whether you agree ordisagree withthem.Place anAintheBefore column What doyou think? . i n eoeSaeetAfter Statement Before d d Temperature Recall thattheparticlesmakeupmatterarealways When snowmeltsafterasnowstorm,allthreestatesof

7 4. 3. When asolidmelts, thermalenergy isremoved from thesolid. energy.and kinetic Particles ofmatter have bothpotential energy isameasure oftheaverage energy kinetic ofallthe Within agivensubstance,risein Thefasterparticlesmove,themorekinetic Readthetwo statements below anddecide kinetic energy,kinetic theenergy anobject you studyotherchapters. definitions to refer to when Keep alistofthesewords and look itupinthedictionary. word reading after thelesson, you stilldonotunderstanda words you donotknow. If this lessonandcircle any Building Vocabulary • • • Key Concepts 1. Relate motion? particle temperature related to another? changes from onestate to energy whenmatter What happensto thermal thermal energy different? How are temperature and motion? to particle How istemperature related Key Concept Check How is Skim Skim

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0 1 / 5 2 / Copyright © Glencoe/McGraw-Hill, a division of The McGraw-Hill Companies, Inc. 22/25/10 2:50:16 PM toward Earth. the ball to fall the ball is the total potential and kinetic energies of is the total potential and kinetic energies The energy of particles is due The chemical potential You can change an object’s state of by can change an object’s You Thermal energy Thermal Particles move slower (less kinetic energy). Particles get closer together (less potential energy). Particles move slower and closer together (less kinetic and potential energy). Particles move faster (increased kinetic energy). Particles move faster (increased Particles get farther apart (increased potential energy). Particles get faster and move farther apart (increased kinetic and potential energy).

• • • • • • Potential energy typically increases when objects get farther typically increases when objects Potential energy You can think of the potential energy of particles in a can think of the potential You changes in thermal Changes in state are caused by In addition to kinetic energy, particles have potential potential have particles energy, to kinetic In addition when it is falling from your hands. It has a higher potential from your hands. It has a higher when it is falling is it is falling. When the basketball energy than when The energy. it has no more potential touching the ground, the greater its surface, is from Earth’s farther an object is. As the ball gets closer to the gravitational potential energy ground, its potential energy decreases. Before you let the ball go, it has potential, or stored, energy. stored, energy. ball go, it has potential, or Before you let the When when objects get closer together. apart. It decreases than it is farther off the ground you hold up a basketball, distances between particles increase or decrease. Thus,distances between particles increase greater chemical potentialparticles that are farther apart have together. energy than particles that are closer energy. an object. When you add thermal adding or removing thermal energy. can happen: energy to an object, these things similar way. similar way. particles. The chemicalto their position relative to other and decreases as thepotential energy of particles increases energy. Recall that potential energy is stored energy due to the is stored energy potential energy Recall that energy. holding Think about or objects. between particles interactions force gravitational it go. The and then letting a basketball causes the ball and Earth between If enough thermal energy is added or removed, a change of state can occur. The opposite is true when you remove thermal energy: Thermal Energy Thermal Potential Energy Potential How do How 8

d d Imagine two Which has more Which has more n i . 8 0 4 9 8 8 Key Concept Check Concept Key _ 2 Reading Check L _ of Matter States Reading Essentials E R _ 4 balls connected by a spring. a spring. balls connected by In which arrangement do the potential more balls have energy: pulled when they are apart closer or when they are together? 102

4. Contrast 4. Contrast 3. Model

2. Apply temperature differ? temperature thermal energy and thermal energy potential energy:potential a baseball the ground held 1 m above m above or a baseball held 2 the ground? 1 0 _ 7 0 0 _ 3 1 3 CC313_007_014_RE_L2_889408.indd 8 CC313_007_014_RE_L2_889408.indd 9 3 1 3 _ 0 0 7 _ 0 1 4 _ R E

_ Copyright © Glencoe/McGraw-Hill, a division of The McGraw-Hill Companies, Inc. L 2 _ 8 8 9 4 0 edn setas ttso atr States ofMatter Reading Essentials Energy Changes toLiquidor Solid as shownbyatemperatureincrease. will causethekineticenergyofparticlestoincreaseagain, Once asolidcompletelymelts,theadditionofthermalenergy The particlesmovefartherapartandpotentialenergyincreases. energy causestheparticlestoovercome theirattractiveforces. to increase.Howisthispossible? increasing. However, theamountofthermalenergycontinues means that thetemperature,oraveragekineticenergy, stops Notice thatthelineongraphbelowishorizontal.This However, energychangesstilloccur. from solidtoliquid,thetemperaturedoesnotchange. which thesolidchangestoaliquid.Asaluminum point ofthematter. Themeltingpointisthetemperatureat The temperaturestopsrisingwhenitreachesthemelting thermal energy(potential relationship betweenincreasingtemperatureand thermal energymustbeadded.Thegraphbelowshowsthe aluminum cans.To changematterfromasolidtoliquid, another byaddingorremovingthermalenergy. a processthatinvolvesmatterchangingfromonestateto you recyclethecan?Aluminumrecyclingisoneexampleof 8 . i n

d Temperature Increases d What happenswhenasolidreachesitsmeltingpoint? At first,thethermalenergyandtemperatureincrease. The firstpartoftherecyclingprocessinvolvesmelting After youdrinkabeveragefromanaluminumcan,do Once asolidreachesthemeltingpoint,additionalthermal

9 Thermal Energyv. Temperature to Liquid Changes asSolid PE littlechange T increases Solid + kineticenergy). Thermal EnergyIncreases T constant Melting PE increases T increases Liquid PE littlechange remains constant? melting, whichfactor 6. Analyze 5. Infer from asolidto aliquid? added to matter to changeit PE kinetic energy) T = = Visual Check Reading Check potential energy potential temperature(average What mustbe During 103 22/25/10 2:50:29PM / 2 5 / 1 0

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The figure below Bubbles, or vaporized or vaporized Bubbles, particles, the top rise to of the liquid and escape the container. from . Vaporization that occurs within a liquid is called . that occurs within a liquid is called Vaporization After the aluminum melts, it is poured into molds to molds into it is poured melts, the aluminum After notice how bubbles do you ever water, When you During boiling, a During boiling, liquid vaporizes its surfaceat and within the liquid. Boiling and in the liquid. place throughout the During boiling, vaporization takes boiling occurs in a liquid liquid. The temperature at which point. called its boiling is take place as liquid aluminum forms solid blocks, move from aluminum forms solid blocks, take place as liquid the graph on the previous page. right to left on rise to the surface? The begin to form at the bottom and a . As the water , it bubbles contain , the gaseous state. changes from the liquid state to in state of a liquid into a gas is and boiling. shows two types of vaporization—evaporation differ in where they take place The two types of vaporization cool. As the aluminum cools, thermal energy leaves it. If energy leaves it. cools, thermal the aluminum cool. As will freeze. the aluminum energy is removed, enough changes opposite of melting—liquid that is the is a process the changes from at which matter The temperature to solid. can You solid state is its freezing point. liquid state to the page to of melting on the previous look at the graph To as thermal energy is removed. the process of freezing observe changes that temperature and thermal energy the Boiling Liquid to GasLiquid to or Gas to Liquid Freezing During evaporation, During evaporation, a liquid vaporizes its surface.only at 0 1

Why doesn’t doesn’t Why d d n freezing. i .

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8. Explain 7. Define the evaporation flask have the evaporation flask have the surface?bubbles below 1 0 _ 7 0 0 _ 3 1 3 CC313_007_014_RE_L2_889408.indd 10 CC313_007_014_RE_L2_889408.indd 11 3 1 3 _ 0 0 7 _ 0 1 4 _ R E

_ Copyright © Glencoe/McGraw-Hill, a division of The McGraw-Hill Companies, Inc. L 2 _ 8 8 9 4 0 edn setas ttso atr States ofMatter Reading Essentials toGas Solid toSolid orGas toGas Solid Evaporation the surroundingair, creatingathickfog. icesublimes,itcoolsandcondensesthewatervaporin dry state from asolidtogaswithoutgoingthrough theliquidstate. The processiscalledsublimation. immediately intoagaswhenthermalenergyisaddedtoit. Also, agascanbecomesolidwithoutturningintoliquid. blades ofgrassandformsdew. condensation. condenses. enough thermalenergy, thegaschangestoaliquid,or to agas.Theoppositeprocessalsooccurs.Whengasloses container willdisappearafterseveraldaysduetoevaporation. ofaliquid.the surface to increaseagainasshownonthegraphabove. begins toincreaseagain.Therefore,thetemperature continues tobeadded,thekineticenergyofgasparticles changes toagas.Whenboilingends,ifthermalenergy forces nolongerholdthemtogether. Atthispoint,the liquid increasing. The ,thepotentialenergyofparticlesbegins increases untiltheliquidreachesitsboilingpoint.At as thermalenergyisadded.Thekineticofparticles 8 . i n Temperature Increases d d In thegraphabove,noticeenergychangesthatoccur A solidcanbecomeagaswithoutturningintoliquid. Boiling andevaporationareprocessesthatchangealiquid Unlike boiling,

1 1 PE littlechange T increases Liquid The changeofstatefrom agastoliquidiscalled Dry iceissolidcarbondioxide.Itturns Dry Overnight,watervaporoftencondenseson particles move farther apart until the attractive particles movefartherapartuntiltheattractive Thermal Energyv. Temperature evaporation Asmallamountofliquidinanopen Thermal EnergyIncreases as Liquid Changes to Gas as LiquidChanges PE increases T constant Boiling isvaporization thatoccurs onlyat Sublimation PE kinetic energy) T = = potential energy potential temperature(average PE littlechange T increases Gas isthechangeof As what state ofmatter? the aircondenses. Cloudsare form whenwater vaporin liquid changeto agas? 10. Apply each term underthetabs. record whatyou learnabout afour-tabMake Foldable and 9. Explain

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Condensation Vaporization


Deposition Evaporation can Why doesthe 105 22/25/10 2:50:47PM / 2 5 / 1 0

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0 1 / 5 2 / Copyright © Glencoe/McGraw-Hill, a division of The McGraw-Hill Companies, Inc. 22/25/10 2:50:53 PM temperature (average temperature potential potential energy = = T kinetic energy) kinetic PE Gas T increases PE little change Boiling T constant PE increases For deposition to happen, thermal to happen, For deposition The opposite of sublimation is deposition. is deposition. of sublimation opposite The Liquid T increases PE little change is the change of state of a gas to a solid without going without a solid of a gas to of state change is the Thermal Energy Increases The Heating Curve of Water Curve The Heating of At 0°C, the of water, the water molecules At 0°C, the melting point of water, boiling point, liquid water When water reaches 100°C, its Water is the only substance that exists naturally as a solid, the only substance that exists is Water The hot a beaker of on a hot plate. Suppose you place to overcome their attractive forces, and melting occurs. Once forces, their attractive to overcome energy of the particles begins melting is complete, the kinetic energy is added. Then the to increase again as more thermal too. temperature begins to increase, Again, kinetic energy stays begins to change to water vapor. When the change of state is the same as vaporization occurs. molecules increases again, complete, the kinetic energy of and so does the temperature. understand the energy changes during a change in state, look energy changes during a change understand the at the heating curve shown in the graph below. of water the beaker and the ice. The plate moves thermal energy to Recall that this means the temperature of the ice increases. molecules increases. average kinetic energy of the water to move out of their places. vibrate so rapidly that they begin energy causes the particles At this point, any added thermal a liquid, and a gas within Earth’s temperature range. To better To temperature range. within Earth’s a liquid, and a gas Deposition the liquid state. through on a on grass from the gas. be removed energy must vapor As water result of deposition. is often the fall morning into solid frost. it changes energy, loses thermal Adding Thermal Thermal Adding Energy Gas to Solid Water of States Solid T increases PE little change Melting T constant PE increases Why are are Why 2 the changes 1

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d d n i . 8 0 4 9 8 C C 8 ° ° Key Concept Check Concept Key _ 0 2 Reading Check Reading L

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of Matter States Reading Essentials 100 E Temperature Temperature R _ 4 sublimation and deposition and deposition sublimation of state? unusual changes 106 13. Locate

12. Describe

11. Evaluate 11. Evaluate in thermal energy as water as water in thermal energy a liquid. a solid to goes from water reaches its boiling reaches water point. location on the graph where where location on the graph 1 0 _ 7 0 0 _ 3 1 3 CC313_007_014_RE_L2_889408.indd 12 CC313_007_014_RE_L2_889408.indd 13 3 1 3 _ 0 0 7 _ 0 1 4 _ R E

_ Copyright © Glencoe/McGraw-Hill, a division of The McGraw-Hill Companies, Inc. L 2 _ 8 8 9 4 0 energy isalsoconserved. the matterandsurroundingmatter, youwouldfindthat absorbs thermalenergy. Ifyoumeasuredthermalenergyin edn setas ttso atr States ofMatter Reading Essentials Conservation ofMassandEnergy Energy Removing Thermal conserved. conserved. remaining m Ifthegaswerecapturedanditsmassaddedto gas. have disappeared.However, ithasjustformedaninvisible always conserved. During allofthesechangesstate,matterandenergyare Notice thattherearethreesetsofoppositeprocesses: place asthermalenergyisaddedorremovedfrommatter. the waterfurtherchangesittoice. left. Coolingwatervaporchangesthegastoaliquid. by followingthegraphonpreviouspagefromrightto what happenstowatervaporasyouremovethermalenergy ofwater.process shownintheheatingcurve You canfollow 8 . i n d d Sometimes, suchaswhenwatervaporizes,itseemsto Thesameistrueforenergy. Surroundingmatteroften The diagrambelowshowstheenergychangesthattake The removalofthermalenergyisthereverse • • •


1 3 sublimation anddeposition vaporization andcondensation melting andfreezing ass oftheliquid,youwouldseethatmatteris remove thermalenergy add thermalenergy Freezing Melting Changes ofState remove thermalenergy add thermalenergy Sublimation Deposition Liquid remove thermalenergy add thermalenergy Condensation Vaporization 15. Draw 14. Describe a liquid. thermal energy isaddedto of matter thatresults when energy isremoved from it. to water vaporwhenthermal Visual Check Reading Check Circle thestate what happens what happens Gas 107 22/25/10 2:51:04PM / 2 5 / 1 0

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0 1 / 5 2 / Copyright © Glencoe/McGraw-Hill, a division of The McGraw-Hill Companies, Inc. 22/25/10 2:51:11 PM END OF LESSON condensation the total potential and kinetic energies of of energies and kinetic potential the total Happens When Happens When ED a measure of the average kinetic energy of all of all kinetic energy average of the a measure the change in state of a liquid into a gas of a liquid into the change in state the change of state from a solid to a gas without without a gas a solid to from of state the change Thermal Energy Is Removed Energy Thermal onnect C going through the liquid state the going through an object the particles in an object Log on to ConnectED.mcgraw-hill.com ConnectED.mcgraw-hill.com on to Log find this to textbook your and access resources. lesson’s sublimation: sublimation: temperature: thermal energy: vaporization: melting sublimation Happens When Happens When 4 the energy an object its motion the energy has due to 1

the change of state from a gas to a liquid a gas to from of state the change

Thermal Energy Is Added Energy Thermal d vaporization that occurs only at the surface at only occurs of that vaporization d the change of state of a gas to a solid without without a solid a gas to of of state the change n i . 8 0 4 9 8 8 _ 2 L a liquid going through the liquid state going through _ of Matter States Reading Essentials E Name two types of vaporization. How are they different? Write the correct term next to its opposite term in each row of the table below. the correct term next to its opposite Write Review the terms and their definitions in the Mini Glossary. Write a sentence that Write Mini Glossary. and their definitions in the Review the terms its opposite process. of one change of state and includes an example agree with the statement or a D if you disagree. disagree. or a D if you the statement with agree mind? change your Did you Reread the statements at the beginning of the at the beginning the statements Reread with an A if you column in the After lesson. Fill R What do you think _ 4 108 3. 2. 1. evaporation: evaporation: kinetic energy: Mini Glossary condensation: deposition: 1 0 _ 7 0 0 _ 3 1 3 CC313_007_014_RE_L2_889408.indd 14