16-Principles of Chemical Equilibrium .pdf

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1、Chemistry140Fall2002Chapter16:PrinciplesofChemicalEquilibrium化学平衡原理Contents16-1DynamicEquilibrium16-2TheEquilibriumConstantExpression16-3RelationshipsInvolvingEquilibriumConstants16-4TheSignificanceoftheMagnitudeofanEquilibriumConstant16-5TheReactionQuotient,Q:

2、PredictingtheDirectionofaNetChange16-6AlteringEquilibriumConditions:LeChâtelliersPrinciple16-7EquilibriumCalculations:SomeIllustrativeExamples化学化工学院刘巍Slide2of451Chemistry140Fall200216-1DynamicEquilibrium•Equilibrium–twoopposingprocessestakingplaceatequalrates.•

3、可逆反应速率相等时的状态H2O(l)¾H2O(g)HO2NaCl(s)¾NaCl(aq)CO(g)+2H2(g)¾CH3OH(g)I2(H2O)¾I2(CCl4)化学化工学院刘巍Slide3of4516-2TheEquilibriumConstantExpressionk12Forward:CO(g)+2H2(g)→CH3OH(g)Rfwrd=k1[CO][H2]k-1Reverse:CH3OH(g)→CO(g)+2H2(g)Rrvrs=k-1[CH3OH]AtEquilibrium:k1Rfwrd=RrvrsCO(

4、g)+2H2(g)¾CH3OH(g)k-1k1[CO][H2]2=k-1[CH3OH]k1[CH3OH]==Kck-1[CO][H2]2化学化工学院刘巍Slide4of452Chemistry140Fall2002ThreeApproachestoEquilibrium化学化工学院刘巍Slide5of45ThreeApproachestotheEquilibrium化学化工学院刘巍Slide6of453Chemistry140Fall2002ThreeApproachestoEquilibriumk1CO(g)+2H

5、2(g)¾CH3OH(g)k-1[CH3OH][CH3OH][CH3OH]Kc=2[CO][H2][CO](2[H2])[CO][H2]Kc(1)=1.19M-10.596M-114.2M-2Kc(2)=2.17M-11.09M-114.2M-2Kc(3)=2.55M-11.28M-114.2M-2化学化工学院刘巍Slide7of45GeneralExpressionsaA+bB….→gG+hH….[G]g[H]h….Equilibriumconstant=Kc=[A]m[B]n….Thermodynamic(aG)

6、g(aH)h….Equilibriumconstant=Keq=(a)a(a)b….AB[B]a==g[B]c0isastandardreferencestateBc0BBB=1molL-1(idealconditions)化学化工学院刘巍Slide8of454Chemistry140Fall200216-3RelationshipsInvolvingtheEquilibriumConstant•ReversinganequationcausesinversionofK.（正逆反应的平衡常数）CO(g)+2H(g)¾

7、CHOH(g)23[CH3OH]K＝[CO][H]22CHOH(g)¾CO(g)+2H(g)32[CO][H]212K’＝=[CH3OH]K化学化工学院刘巍Slide9of4516-3RelationshipsInvolvingtheEquilibriumConstant•Multiplyingbycoefficientsbyacommonfactorraisestheequilibriumconstanttothecorrespondingpower.（反应式乘以系数n，平衡常数为原平衡常数的n次方。)[SO3]S

8、O2(g)+1/2O2(g)¾SO3(g)Kc=1/2[SO2][O2][SO]22SO(g)+O(g)¾2SO(g)K’3=K2223c=2c[SO2][O2]化学化工学院刘巍Slide10of455Chemistry140Fall200216-3RelationshipsInvolvingtheEquilibriumConstant•Div