Freeresponsereview.docx

Freeresponsereview.docx

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Freeresponsereview

Topic2:

Atoms,moleculesandionsFreeResponsePractice

1.Thetwostableisotopesofchlorinehavemassesof34.969amuand36.966amu.

a.Whatarethemassnumbersofthetwoisotopesofchlorine?

b.Calculatethe%abundanceofthelighterisotope.

c.Howmanytypesofmoleculeswithdifferentmassesexistinasampleofchlorinegasifthesampleexistsentirelyasdiatomicmolecules?

Explainyouranswer.

d.Calculatethemassofthechlorinemoleculehavingthelargestmolecularmass.

e.Whatisthemassofthemostabundantmolecule?

Calculateits%abundance.

2.Likechlorine,iodineisahalogenandformssimilarcompounds.Writethenamesandformulasofthefouroxyanionsandthefouroxyacidsofiodine.

Topic3StoichiometryFreeResponsePractice

1.Combustionof8.652gramsofacompoundcontainingC,H,O,andNyields11.088gofCO2,3.780gramsofH2Oand3.864gramsofNO2.

a.HowmanymolesofC,H,andNarecontainedinthesample?

b.Howmanygramsofoxygenarecontainedinthesample?

c.Whatisthesimplestformulaofthecompound?

d.Ifthemolarmassofthecompoundliesbetween200and300,whatisitsmolecularformula?

e.Writeandbalanceachemicalequationforthecombustionofthecompound.

Topic4SolutionStoichiometryFreeResponsePractice

1.Philaccidentallyspillsa1.00Lbottleofconcentrated18.0Msulfuricacidonthefloor.Heattemptstoneutralizethespillbypouringa5.00kgboxofbakingsodaontotheacid.

a.Writeabalancednetionicequationforthereaction.Assumetheconcentratedsulfuricacidis100%pureandnotinaqueoussolution.

b.Whatisthelimitingreactant?

c.Howmanygramsofbakingsodaarerequiredtoneutralizetheacid?

d.Howmanymolesofexcessacidremainsafterallthelimitingreactanthasbeenconsumed?

e.Wouldafloorconsistingofbareconcreterequiremore,lessorthesameamountofbakingsodatoneutralizethespill?

Explain.

2.ThreeunknownacidsolutionsarelabeledA,B,andC.Oneissulfuricacid,oneishydrochloricacid,andtheotherisnitricacid.Eachhasaconcentrationofapproximatelyonemolar.Usingonlyaqueousreagentsof0.20Mlead（II）nitrateand0.50Mcalciumnitratewriteashort,conciseexperimentalprocedure,theresultsofwhichwillbesufficienttoidentifyeachoftheunknownacids.Tellwhatyouwouldexpecttoseeandwhatitmeans.Writenetionicequationstoillustrateyouranswers.

Topic5Thermo-chemistryFreeResponsePractice

1.Theheatofcombustionofgaseousbutaneis-2658kJ/molandtheheatofcombustionofliquidbutaneis–2635kJ/molwheninbothcases,allproductsaregases.

a.Writeabalancedchemicalequationforthecombustionofgaseousbutane.

b.Howmanygramsofgaseousbutanecombustwhen1550kJofheatareproduced?

c.Whatisthemagnitudeandsignofthemolarheatofvaporizationofbutane?

ExplainyourreasoningusingHess’slaw.Isyoursignfortheheatofvaporizationrealistic?

Explain.

2.When15.0gramsofpropanearecombustedinairtoproduceallgaseousproducts,73.00kJofheatareproduced.

a.Calculatethemolarheatofcombustionofpropane.

b.When15.00gofpropanearecombustedinairtoproducegaseouscarbondioxideandliquidwater,790.0kJofheatareproduced.Explainwhytheamountofheatavailablefromthecombustionofpropanedependsonthephaseoftheproducts

c.CalculatetheheatofvaporizationofwaterinunitsofkJ/g.

Topic6ElectronicStructureofAtomsFreeResponsePractice

1.Alinehavingawavelengthof656nmexistsintheatomicemissionspectrumofhydrogen.

a.Fortheline,calculatethefollowingvaluesandspecifytheirunits:

i.Frequency

ii.Energyofaphoton

iii.Energyofamoleofphotons

b.Whatcoloristheline?

Explainyourreasoning.

c.DiscusstheoriginofthelineintermsoftheBohrtheoryoftheatom.Specifyanyenergytransitionsthatareapplicable.

2.Moleculesofoxygenareconvertedtoatomicoxygenintheupperatmospherebyabsorbingphotonshavingwavelengthsof240nmandshorter.

a.Writetheelectronconfigurationofoxygenandtellwhyatomicoxygenisdiamagneticorparamagnetic.

b.Writetheelectronconfigurationfortheoxideion.Assignasetoffourquantumnumberstoeachoftheelectronsintheoxideion.Correlatethesetstotheelectronconfiguration.

c.Calculatetheenergyequivalentofaphotonofwavelength240nminunitsofkJ/mol.

Topic7PeriodicPropertiesoftheElementsFreeResponsePractice

1.Usedetailsofthemodernatomictheoryandperiodicitytoexplainwhy:

a.Atomicradiibecomelargerastheatomicnumberwithinafamilygetslarger.

b.Atomicradiibecomesmallerastheatomicnumberwithinaperiodgetslarger.

c.Theradiusofanoxideionislargerthantheradiusofanoxygenatom.

d.Thefirstionizationenergyofaluminumissmallerthanthefirstionizationenergyofmagnesium

e.Thethirdionizationenergyofanelementisalwayslargerthanitssecondionizationenergy

2.Writetheformulastoshowthereactantsandproductsforthefollowinglaboratorysituations.Balancetheresultingchemicalequationandanswerthequestionabouteach.Besuretowritesubstancesasionsiftheyareextensivelyionizedinsolution.

a.Solidlithiumnitrideisaddedtowater.WhatwouldbetheeffectonpHpaperheldoverthevessel?

b.Solidcalciumisplacedinwater.Whatwouldyouobserve?

c.Solidstrontiumisheatedinthepresenceofbrominegas.Wouldyouexpectthereactiontobeendothermicorexothermic?

Explain.

d.Sulfurdioxideisbubbledthroughwater.Isthisaredoxreaction?

Explain.

e.Magnesiumisheatedindryair.Writetheequationthatrepresentsanotherpossiblereactionforthismixture.

f.Sodiumhydrideismixedwithwater.Writethechemicalequationforthespontaneousignitionofoneoftheproductswithair.

Topic8BasicConceptsofChemicalBondingFreeResponsePractice

1.Considerthefollowingchemicalspecies:

thenitrogenmolecule,thenitriteion,andthenitrateion.

a.Writethechemicalformulasforeachofthespeciesandidentifytheoxidationnumberofthenitrogenatomineachformula.

b.DrawLewisstructuresforeachofthespecies.Whereappropriate,drawresonancestructuresforeach.

c.ListthechemicalspeciesinorderofincreasingN-Obondlength,theformulawiththeshortestbondfirst.Justifyyouranswer.

d.Writeabalancednetionicequationforthereactionofnitrogendioxidewithwater.Commentonthemolecularand/orionicspeciesthatareformed.

e.Draweachoftheresonancestructuresfornitrogenmonoxideandassignformalchargestoeachatomofeachstructure.

2.Carbondioxidegasisbubbledintowater.

a.Writeandbalanceachemicalequationtodescribetheprocess.

b.DrawtheLewisstructuresofthereactantsandproducts.Includeanyvalidresonancestructures.

c.Giventhefollowingbondenthalpies,estimatetheenthalpyofthereaction.

Bond

BondEnthalpy（kJ/mol）

H-H

436

H-O

463

O-O

146

C-O

358

C=O

799

C=O

1072

d.AretheC–Obondsinthereactantshorterorweakerthanthoseistheproduct?

Explain.Isyourexplanationconsistentwiththesignoftheenthalpychangeyouestimated?

Explain.

e.Excessaqueoussodiumhydroxideisaddedtothesolution.Writeandbalanceanetionicequationfortheresultingreaction.

Topic9MolecularGeometryandBondingTheoryFreeResponsePractice

1.ConsiderthechemicalspeciesIF5andIF4+.

a.DrawtheLewisstructureandmakearoughthree-dimensionalsketchofeachspecies.

b.Identifytheorbitalhybridization,theelectron-domaingeometry,andthemoleculargeometryofeach.

c.Identifytheapproximatebondanglesofeachspecies.

d.Predictwhich,ifany,arepolarspecies?

Justifyyouranswer.

e.Predictthemostprobableoxidationnumberoftheiodineatomiseachspecies.GiveanexampleofanotherchemicalspecieshavingthesameoxidationnumberasIF4+.

f.WouldyouexpecttheconversionofIF5toIF4+tobeexothermicofendothermic?

Explain.

2.Considereachofthesemolecules:

C3H4,C3H6,C3H8.

a.DrawtheLewisstructureforeachmoleculeandidentifytheorbitalhybridizationofeachcarbonatom.

b.Specifythegeometryofeachcentralcarbonatom.

c.Writeabalancedequationforthecompletecombustionofeachmolecule.

d.Usethefollowingbondenthalpiestodeterminetheheatofcombustionofeachmolecule.SpecifyyouranswerinkJ/mol.

Bond

kJ/mol

Bond

kJ/mol

C–H

413

O–H

463

C–C

384

O=O

495

C=C

614

C=O

799

C=C

839

C–O

358

Topic10GasesFreeResponsePractice

1.Equalmasses（0.500geach）ofhydrogenandoxygenareplacedinanevacuated4.0Lflaskat25.0°C.Themixtureisallowedtoreacttocompletionandtheflaskisreturnedto25.0°Candallowedtocometoequilibrium.Thevaporpressureofwaterat25.0°Cis23.76torr.

a.Writeandbalanceanequationforthereaction.

b.Whatisthetotalpressureinsidetheflaskbeforethereactionbegins?

c.Whatisthemassofwatervaporintheflaskatequilibrium?

d.Howmanygramsofwhichreactantgasremainsatequilibrium?

e.Whatisthetotalpressureinsidetheflaskatequilibrium?

f.Afterthereaction,isthereanyliquidwaterpresent?

Ifso,howmanygrams?

Ifnot,whynot?

2.A2.00Lflaskat27°Ccontains3.00gramseachofAr,SO2,andHe.Answerthefollowingquestionsaboutthegasesandineachcase,explainyourreasoning.

a.Whichgashasparticleswiththehighestaveragekineticenergy?

b.Whichgashasparticleswiththehighestaveragevelocity?

c.Whichgashasthehighestpartialpressure?

d.Whichgaswilldeviatemostfromidealbehavior?

e.Whichsubstancewillhavethehighestboilingpoint?

f.Whatchangesintemperat