FINAL EXAM REVIEW CHEM 1412 - Welcome to Blinn College期末考试复习化学1412 -欢迎来到宾氏学院

FINALEXAMREVIEW

CHEM1411Fall2021YouwillneedtobringapictureID.Pencilsandcalculator(nonprogrammable).TheExamisSaturdayDec.6at9:00amCPCRoomTBA

TheexamisEXACTLY2Hoursinlength. Beinglatecostsyoutimeontheexam. Nottakingthefinal=0forFinalexamgrade THEREARENOMAKE-UPFINALSChapter1

CHEMISTRY:MATTERANDMEASUREMENT

ChemicalChangesPhysicalChangesChemicalPropertiesPhysicalPropertiesDimensionalAnalysis (UnitFactorMethod)DensityChemicalProperties–chemicalchangesChangesinchemicalcompositionRelativereactivityPhysicalProperties–physicalchangeschangesofstate,compositionremainsconstantdensity,color,solubilityExtensiveProperties–dependonamountpresentIntensiveProperties–physicalorchemicalpropertiesthatareindependentofamountpresent.Chapter1

CHEMISTRY:MATTERANDMEASUREMENTChapter1

CHEMISTRY:MATTERANDMEASUREMENTDensityChapter2

Atoms,Molecules,andIonsIsotopesAtomicNumberAtomicMassChemicalcompoundsMixturesNamesandFormulasofIonicCompoundsMolecular/FormulaWeightEmpiricalFormulasMolecularFormulasCovalentbonds/CovalentcompoundsMassNumberandIsotopes Themassnumberofanelement(specificallytheisotopeoftheelement)isgiventhesymbolA. Aissumofprotons+neutronsSpecificisotopesofanelement(E)canbeshownasA=massnumberZ=atomicnumberN=neutronsinthatisotopeAtomicWeightsThisisthelowernumberonperiodicchartThisisweightedaverageofthemassesoftheconstituentisotopesnaturallyoccurring.CompoundsandMixturesMatterMixturesPure

SubstancesHeterogeneousHomogeneousElementsChemical

CompoundsMixturescomposedoftwoormoresubstancesinvariableratioscanbeseparatedintocomponentsbysimplephysicalorchemicalmethodshomogeneousmixtures

–cannotbeseparatedbyphysicalinspectionheterogeneousmixtures

–usuallycanbeseparatedbysimplephysicalmeansCompoundsandMixturesChemicalBonding

Chemicalbondingistheattractiveforcesthatholdatomstogether.

Covalentbondsresultfromthesharingoftwo(usually)ormoreelectronsbetween2atoms.

Ionicbondsareelectrostaticforcesdescribingtheattractionbetweenpositiveandnegativeions.IonicorCovalent?Isthecompoundionicorcovalent? Generallycovalentbondsconsistofnonmetals(usually)sharingelectrons.

Ionicbondsexistbetweenmetalsandnonmetals(usually)–themetalgaveupitselectrontothenonmetal.

Polyatomicionshavecovalentbondsbutalsocarryacharge.NamingCompounds Byconvention,chemicalformulasarewrittenwiththemostpositiveelementlistedfirst.

Binaryioniccompounds.Formetalionsyouonlyneedtoindicatethechargeontheion(usuallynecessaryfortransitionandpost-transitionmetals).Thenumberofthationpresentisassumed.

Binarycovalentcompounds.Fornonmetals,aprefixisonlyusedforthecation(firstelementlisted)ifmorethanoneatomispresent.Sincenonmetalsmaycombineinnumerousratios,theanionportionofthenamealwaysisgivenwithanumericalprefix.Chapter3

Formulas,Equations,andMoles

ChemicalEquations(includingbalancing)CalculationsBasedonChemicalEquationsLimitingReactantConcentrationofSolutionsUsingSolutionsinChemicalReactions%CompositionandempericalformulasMolecularformulasvsmolecularmassChemicalEquationsConsideratypicalreaction:reactantsorstartingmaterialsyieldsorproducesproductswithheatingThecoefficientsrepresentthenumberofmoles(orparticles)neededforthecompletereaction.Nocoefficientisunderstoodtobe“1〞.Considerthesenumberstoberatios.TheMole Thetermmoleisashorthandabbreviationof“gramformulamolecularweight〞 gramformulamolecularweightgrammolecularweightmolecularweightmol.weightmol.wt.molYouneedtomakemolesyourfriends(oratleastallies)oryouwillnotsurvivethecourse.mol.ormolwasspelledmole

(likeitsounds)

Avogadro’snumber=6.022

1023ConcentrationofSolutionsNomenclaturesolution amixtureoftwoormoresubstances,usuallyoneisaliquidsolvent thematerialdoingthedissolving(usuallythemostabundantmaterialortheliquid)solute thematerialthatisdissolved(usuallytheleastabundantmaterial)concentration theamountofsolutedissolvedinasolvent,canbeexpressedinpercent(%),molarity(M),normality,(N),ormolality(m)DilutionofSolutionsMolaritydilutionproblemscanbeeasytosolve.SincethenumberofmolesremainsconstantM1=molaritysolution1V2=volumesolution2M2=molaritysolution2V1=volumesolution1YoumayuseeitherLormL(thesemustbethesameunits)tosolvetheproblem.TitrationCalculations

Dothemoleschange--NODothemoleschange--YESAdjustmolesTitrations Titrationisamethodtoexactlythedeterminetheconcentrationofasolution. Titrationsrequirestandards–materialswhoseconcentrationscanbeexactly(accurately)determinedspecialglassware–buretsandpipets,thesehavebeencalibratedtobeaccurateto0.01mLorless(0.001mL)indicators–to“indicate〞whenthetitrationisfinished Thisallowsconcentrationstobedeterminedto4decimalplaces(min.4significantfigures)PercentComposition

andChemicalFormulas Example24:Acompoundcontains24.74%K;34.76%Mn;and40.50%Obymass.Whatisitsempiricalformula?Formula:

KMnO4Chapter4

SOMETYPESOF

CHEMICALREACTIONSAcid/BaseReactionsPrecipitationReactionsOxidation/ReductionReactions IncludingOxidationNumbersFormulaUnitEquations(molecular)TotalIonicEquationsNetIonicEquationsBalancingRedoxreactionsAcid-BaseReactions Thereactionofanacidandabaseproducesasaltand(usually)water. Bydefinition,neitheranacidnorabase(ortheiranhydrides)canbeasalt.Strongacidsandbaseswilldissociateintoions.Weakacidsandbasesareshowninallrepresentationsasthenon-dissociatedmolecules.StrongandWeakAcids

AcidsgenerateH+aqueoussolutions.

Thechemicalformulasforacidsusually

beginwithH. Organicacidsaretheexceptiontothis.TheyendwithCOOHorCO2H.Knowtheseformulaconventions!KNOWTHESTRONGACIDSBYMEMORYStrongSolubleBasesBasesproducehydroxideions,OH–,insolution.Strongsolublebasesionize~100%inwater.KNOWTHESTRONGBASESBYMEMORYSolubilityRules Forthiscourse,solubilitydescribesacompoundsabilitytodissolveinwater. Youmustbeabletopredictwhetheracompoundisorisnotsoluble(thisisexammaterial). All(soluble)strongacidsandallstrongbasesarecompletelywatersoluble. Mostbutnotalloftheirsaltsaresoluble. Therulesforsolubilityareusedtodetermineifaninorganicsaltissoluble.Youmustknowtheserulesbyheart!!!SolubilityRulesSolubleIonicSaltsAllIAmetalsaltsaresoluble.Allammoniumsaltsaresoluble.Allchloridesaresoluble(exceptAg,Hg,andPb).Allnitratesandacetatesaresoluble.Allperchloratesandchloratesaresoluble.Allfluoridesaresoluble(exceptIIAmetalfluorides).Allsulfatesaresoluble(exceptCa,Ba,Sr,Ag,Hg,andPb).SolubilityRulesThe“solubility〞rulesshouldbefollowedfirst.RegardlessallIAmetalsaltsandNH4+aresoluble.InsolubleIonicSalts(IAmetalandammoniumsaltsaresoluble)Allphosphatesareinsoluble.Allcarbonatesareinsoluble(exceptMgwhichismoderatelysoluble)Allsulfidesareinsoluble.Alloxides(exceptthestrongacidandbaseanhydrides).OxidationNumberRulesTheoxidationnumberofanyfree,uncombinedelementiszero.Theoxidationnumberofanelementinasimple(monatomic)ionisthechargeontheion.Intheformulaforanycompound,thesumoftheoxidationnumbersofallelementsinthecompoundiszero.Inapolyatomicion,thesumoftheoxidationnumbersoftheconstituentelementsisequaltothechargeontheion.OxidationNumberRulesHydrogen,H,incombinedform,hastheoxidationnumber+1(usually). Theonlyexceptiontothisisfoundwithmetalhydrides.AcompoundthatiscomposedofthemetalandH.Thisisthehydrideion,H-.Oxygen,O,incombinedform,hastheoxidationnumber–2,(usually). Theexceptionstothisarefoundwithsomemetaloxidesandhydrogenperoxide.Fluorineasfluorideisalways–1.RedoxReactionsGERLEOtheliongoes“GER.〞LosesElectrons–OxidizedGainsElectrons–ReducedReactionsinAqueousSolutionsThereare3methodsofwritingachemicalreaction.MolecularEquation Thisisthetypicalbalancedchemicalequationusuallyseen.Itmayindicatethestateofthereactant:(g)gaseous;(aq)aqueous;(s)solid;(l)liquid–usedforwaterinanaqueoussolution.TotalIonicEquation Thisrepresentationshowsthereactionastheionsormoleculesthatarepresentinthesolution.NetIonicEquation

Thismethodonlyshowstheionsormoleculesthatactuallychangeoraredirectlyinvolvedinthechemicalreaction.Chapter5

Frequency,wavelengthandenergyrelationsdeBrogliewave/particlecalculationsPeriodicPropertiesElectronicStructureofAtomsThequantummechanicalpictureofatomsQuantumNumbersShapesoforbitalsElectronConfigurationShieldingPeriodicityandAtomicStructureElectromagneticRadiationwavelength

l

(Greeklowercaselambda) distancefromthetop(crest)ofonewavetothetopofthenextwaveunitsofdistance-m,cm,Å1Å=1

10–10m=1

10–8cmfrequency

(Greeklowercasenu)

thisissometimesrepresentedas

(italicizedv) numberofcrests(wavelengths)thatpassagivenpointpersecondunitsoffrequency=1/timeors–1orHertz(Hz)ElectromagneticRadiationRelationshipforelectromagneticradiation

c=l

c=velocityoflight3.00

108m/sor3

1010cm/sTheWaveNatureoftheElectron LouisdeBrogliepostulatedthatelectronshavewave-likeproperties ThewavelengthsofelectronsaredescribedbythedeBroglierelationship.QuantumNumbers

QuantumnumbersaresolutionsoftheSchrödinger,Heisenberg&Diracequations Fourquantumnumbersarenecessarytodescribetheenergystatesofelectronsinatomsn–

theprinciplequantumnumber

–subsidiaryquantumnumberm

–magneticquantumnumberms–spinquantumnumberElectronic

ConfigurationsPauliExclusionPrinciple

Notwoelectronsinanatomcanhavethesamesetof4quantumnumbers.AufbauPrinciple

Theelectronthatdistinguishesanelementfromthepreviouselemententersthelowestenergyatomicorbitalavailable.Hund’sRule Electronswilloccupyallorbitalssinglybeforepairingcanbegin.

Thespinsoftheseelectronswillbealigned.AtomicRadii

(AGroupElementsOnly) Atomicradiidescribesthesizeofatoms. Thisincreasesasyougofromtherighttotheleft.(oppositewhatyouwouldthinksincemoree–areadded.) Thisincreasesfromtoptobottom.(asexpected–moreshellsarebeingadded)radiiincreasesradiiincreasesAtomicRadii Thedecreasingradiiacrossaperiodisduetotheshieldingorscreeningeffectoftheinnerelectrons[He]or[Ne],etc. Consequentlytheouterelectronsfeelastrongereffectivenuclearchargethanexpected. Li[He]shieldseffectivechargeis+1 Be[He]shieldseffectivechargeis+2 F[He]shieldseffectivechargeis+7 Na[Ne]shieldseffectivechargeis+1Chapter6

CHEMICALPERIODICITYPeriodicPropertiesoftheElementsAtomicRadiiIonizationEnergyElectronAffinityIonicRadiiElectronegativityChemicalProperties Chemicalpropertiesandthereactivitiesofvariouselementscanbepredictedbasedupontheirelectronicconfigurations. Onlytheoutermostelectronsorvalenceelectronsareinvolvedinchemicalreactivityandproperties.IonizationEnergy-Potential Ionizationenergy,IE,generallyincreasesasyougoacrossaperiod(smallerradii,e–moretightlyheld). ImportantexceptionsatBeandMg,N,andP,becauseofHund’srule Ionizationenergygenerallydecreasesasyougodownagroup(largerradii,e–morelooselyheld).IEdecreasesIEdecreasesIonicRadii Ionicradiiincreasesasyougofromrighttoleftacrosstheperiodictable. Ionicradiiincreasesasyougofromdowntheperiodictable.IonicradiiincreasesIonicradiiincreasesElectronegativity Electronegativity,EN,isthemeasureofthetendencyofanatomtoattractelectronstoitselfincompounds(togainelectrons). ENincreasesasyougofromlefttoright(toF).ElectronegativityincreasesENincreasesENincreasesasyougoupthetable.Born-HaberCycleforNaCl107.3kJ/mol495.8kJ/mol-348.6kJ/mol-787kJ/molNetreaction-411kJ/mol122kJ/molThisisHess’LawcominginChapt8AlkaliMetals(GroupIA) Alkalimetalsareextremelyreactive,thustheyarenotfoundfreeinnature. Thealkalimetalshaveonlyonevalenceelectron(ns1).GroupIAmetalshavelowfirstionizationenergies. Ionizationenergiesdecreasewithincreasingsizeofthealkalimetals. Allthealkalimetalsformstable1+ions. AlltheIAsaltsaresoluble(virtuallynoexceptions)GroupIIAMetals Alkalineearthmetalsaresilverywhite,malleable,ductile,andsomewhatharderthanGroupIAmetals. Allhavetwovalenceelectrons(ns2). TheionizationenergiesaregreaterforGroupIIAthanforGroupIAmetals.TheHalogens(GroupVIIA) ThehalogensgettheirnamefromtheGreekhalogenmeaningsaltformers LiketheIAandVIIIAelements,thefamilialsimilarityispronouncedwithinthegroup Allarehighlyreactive Tendtoreactviafreeradicalmechanism Colorofelementsareduetoformationoffreeradicals ObtainedfromoxidationofhalidesaltsOrderofincreasingeaseofoxidation.Chapter7

CovalentBondsandMolecularStructureCovalentBondingLewisStructurePeriodicPropertiesResonanacePolar/NonpolarbondsFormalChargesMolecularShapesVSEPRDipolemomentMOTheoryVSEPRTheoryVSEPRdictatesthattheregionsofhighelectrondensityaroundthecentralatomareasfarapartaspossibletominimizerepulsions.

Keytothisisthatnonbondedelectronpairsoccupymorespacethanbondedelectronsdo.Therearefivebasicorbitalconfigurations. Theseshapesarebaseduponthenumberofregionsofhighelectrondensitywithinthemolecule.

Molecularshapesarebaseduponthesebasicorbitalconfigurations.ElectronicandMolecular Geometry2OrbitalsTheonlypossiblemoleculargeometryfor2orbitalsislinear.ElectronicandMolecular Geometry3Orbitals3atoms2atomsElectronicandMolecular Geometry4Orbitals4atoms2atoms3atomsElectronicandMolecular Geometry5Orbitals5atoms4atoms2atoms3atomsElectronicandMolecular Geometry6Orbitals6atoms5atoms4atomsValenceBondTheory Covalentbondsareformedby

overlapofatomicorbitals. Atomicorbitalsonthecentralatomcanmixandexchangetheircharacter–

hybridization.

Maximumoverlaporhead-to-headoverlapbondsarecalledsigmabonds,s.

Generallysbondsareformedbyorbitalswithscharacterorhead-onoverlapofaporbital.

Minimumoverlaporside-to-sideoverlapbondsarecalledpibonds,p. Onlyporbitalsmayformpbonds.ValenceBondTheory Hybridized

orvalencebondorbitalshavethesameshapesasVSEPRorbitals.

Nameoforbital Shapeoforbital

sp linear

sp2 trigonalplanar

sp3 tetrahedral

sp3d trigonalbipyramidal

sp3d2 octahedralBondOrder Bondorder(bo)ofamoleculeisdefinedashalfthenumberofelectronsinbondingorbitalsminushalfthenumberofelectronsinantibondingorbitalsorChapter8

EnergyandHeat;KEvsPE1stLawStateFunctionsWorkandPDVandEnthalpyDE=q+w(w=-PDV)DH=DE+PDVStandardstateandstandardheatsofformationPhysicalandChemicalDHCalorimetryandheatcapacitySpecificheatHess’LawBondEnergiesThermochemistry:ChemicalEnergyTheFirstLawofThermodynamicsAlsoknownas

LawofConservationofEnergy

Thetotalamountofenergyintheuniverse isconstant.

Energycanbeconvertedfromoneformtoanotherbutcannotbecreated.TwoDrivingForcesForSystemsSystemstendtowardastateofminimumpotentialenergy.Systemstendtowardastateofmaximumdisorder.Forareactiontobespontaneous(occur),thecombinationthesetwoforcesmustbeenergeticallyfavorable.TheFirstLawofThermodynamicsSomeThermodynamicTerms StateFunctions

-propertiesofasystemthatdependonlyonthestateofthesystemandareindependentofpathway.

Propertiesthatdependonlyonvaluesofstatefunctionsarealsostatefunctions.

P,V,T,etc.EnthalpyChange,DHDH

enthalpychangechangeinheatcontentatconstantpressure

unlessvolumechangeisprevented,thereactionsarerunatconstantpressureDH=qPDHrxn

heatofreactionDHrxn=SHproducts

SHreactants

DHrxn=SHsubstancesproduced

SHsubstancesconsumedChangesinInternalEnergy,DEChangesinInternalEnergy,DE Inmostchemicalandphysicalchanges,theonlykindofworkispressure-volumework. Pressureisforceperunitarea.

EnthalpyChange,DHand

DEForreactionsinwhichthevolumechangeisverysmallorequaltozeroThisiswhymanyreactionsareruninabombcalorimeter.TheLiquidState

Specificheat

–theenergyrequiredtoraise1gofasubstance1°C

Molarheatcapacity

–theenergyrequiredtoraise1moleofasubstance1°C Energyisgenerallycalculatedinjoules,JorkJ(1000J=1kJ) Calories(cal)areanolderunitofheattransferandaredefinedastheamountofenergyrequiredtoraise1gofwater1°C.TheLiquidStateHeatTransferInvolvingLiquidsThissamegeneralformulaisusedforthecalculationofenergychangesinsolidsandgases.Hess’sLaw

Hess’sLawofHeatSummation–theenthalpychangeforareactionisthesamewhetheritoccursbyonesteporbyany(hypothetical)seriesofstepsthereactionisexothermic(–DH)Hess’sLawallowsthereactiontoberewritteninthereversedirectionthereversereactionisendothermic(+DH)BondEnergies

Bondenergy-amountofenergyrequiredtobreakthebondandseparatetheatoms(gasphase)Bondbreakingisendothermic;bondformationisexothermic.Chapter9

GASES:TheirPropertiesandBehaviorSTPCombinedGasLawEquationIdealGasEquationPartialPressureandDalton’sLawMoleFractionGraham’sLawDeviationsfromIdealityIdealGasLawCombinedGasLawStandardTemperature&PressureSTP

P=1.00000atmor101.3kPaor760torr

T=273Kor0°C

STPisadefinedvalue.Youwillseethisfrequentlyinproblems,quizzesandonexamsandwillbeexpectedtoknowitsvaluesbymemory.RealGasesThevanderWaals’sequationisamethodofcorrectingfordeviationsfromidealgasbehaviorduetotheintermolecularinteractionbetweenthemoleculesandthevolumetheyoccupy.aandbarevanderWaal’sconstants

aistheintermolecularattractiveforce

bisthemeasuredmolecularvolumeofthegasThesevaluesaredeterminedexperimentallyforeachgas.AthighTorlowP,usetheidealgaslaw.Dalton’sLawofPartialPressures Ifyouhaveamixtureofgases,thetotalnumberofmolesofgaspresentitequaltothesumofthemolesofeachkindofgaspresent.Dalton’sLawofPartialPressures

Thetotalpressureexertedbyamixtureofidealgasesisthesumofthepartialpressuresoftheindividualgases.(atconstantTandV)MoleFractionMolefraction

Themolefraction,X,isthenumberofmolesofonecomponentpermolesofallthecomponentsofthesolution. QuiteliterallythisisafractionusingmolesasboththenumeratoranddenominatorFora2componentsolutionGraham’sLaw:

Effusion&Diffusiondiffusion

–interminglingofgaseseffusion

–gasespassthroughporouscontainers ratesareinverselyproportionaltosquarerootsofmolecularweightsordensitiesChapter10

LIQUIDSANDSOLIDSTheLiquidStateHeattransferinvolvingliquidsTheSolidStateHeattransferinvolvingsolidsPhasediagramsPhaseChangesIntermolecularAttractionsandPhaseChangesTheenergyofattractionbetweentwoionsisgivenby:Generallyitisthemagnitude

ofthechargeandnotthenumberofionswiththatchargethatareconsideredwhenevaluatingthisstrengthofattraction.IntermolecularAttractionsandPhaseChangesDipole-dipoleinteractions Theseareweakelectrostaticattractionsbetweenthepolarizedmolecules.IntermolecularAttractionsandPhaseChangesHydrogenbonding ThisisarelativelystrongattractionbetweenaHattachedtoaN,F,orOtoanotherN,F,orOinthesolution.IntermolecularAttractionsandPhaseChangesLondonForces Theseareveryweak

attractiveforcescausedbyinduceddipolemoments. LondonForcesarealsoknownasdispersionforces.IsolatedAratomTemporaryinduceddipolemomentsLiquidsandSolidsHeattransfer Beabletocalculatetheenergyrequiredorreleasedwhenamaterialchangestemperature. Remembertoaddintheenergyrequiredforthephasechange(notemperaturechangeinvolved). Beawareofunitsusedineachproblem.LiquidsandSolidsPhaseChangesMeltingpoint/fr