Chapter 9_1

主讲：张鑫[e-mail]Tel:[phone]PhysicalChemistry(II)1.Atkins’PhysicalChemistry,PeterAtkins&JuliodePaula,Oxford,7thEdition,2002(影印版，高等教育出版社，2006)2.物理化学，天津大学王正烈等，高等教育出版社,第四版答疑：每周四晚上：19:30—21:00,团委西小平房７＃OutcomesofthissemesterHomeworks20%Occasionalquizzes10%Presentations20%FinalExaminations60%dGVdPSdTVSTUHAG+-dAPdVSdTdUTdSPdVdHVdPTdSPTPSVPTTVSPVTSVTPVSSPTVPSReviewPhysicalchemistry(I)AUTSGHTS'UQWQPdVW,VPQUQHPVnRTdSQTmmTVdTdPH212111ln()vapmHPPRTT,,CBBBTPnGGn,,,AAABxBBbBBcBBPPxPkxkbkc()()()lnlnBlBlBlBBBRTaRTxfLOGOPhysicalChemistry(II)Textbook:Atkins’sChapter9Reference:天大上册第五章Chapter9ChemicalEquilibriumDirectionofProcessorReactionThermodynamicsTopicsExtentofReactionBackgroundofChemicalEquilibriumCase1_AmmoniasynthesisN2+3H2→2NH31.ImportantinAgriculture2.HaberwonNobelPrizebyusingFecatalyst322()2*()()3*()2*(16.45)0032.9/tanmrmBfrmrmrmrmrmGvGBGGNHGNGHGkJmolSponeousDifficulttooccur,N≡NisinerttodissociationConditions:500-600oC,200atm,FecatalystCase2_WaterdecompositonH2O→H2+0.5O21.Importantforfutureenergy2.WhowillwonNobelPrize?CanYou?CanI?222()()0.5*()*()00(237.129)237.129/tanmrmBfrmrmrmrmrmGvGBGGHGOGHOGkJmolThereverseissponeous25oC,Kө=2.7*10-42;α=2.7*10-282000oC,Kө=2.1*10-3;α=0.02KeyIssuesoftheChemicalEquilibrium2QuantitativeeffectsofChangesinp,T,andpHK=f(p,T,pH)3PredicttheequilibriumcompositionunderanyreactionconditionsK－xiK－1EstablishtherelationshipbetweentheequilibriumconstantandthestandardGibbsenergyofreactionrGImportanceofPracticalPurposePredictthehighestyieldinaprocessorreaction312ControltheYieldbychangingConditions(T,p,andpH)DevelopmentofChemicalEquilibrium1861～1863Berthelot,deSaintGilles（法）提出逆反应和动态平衡的概念1864～1879Guldberg-Waage(挪威）建立了质量作用定律，提出了平衡时正逆反应速率相等，正逆反应速率常数之比只是温度的函数vantHoff定义平衡常数KDevelopmentofChemicalEquilibrium1878Gibbs用化学势导出了平衡条件1884LeChatelier平衡移动原理1889vantHoff平衡常数与温度的关系方程1970‘sISO(InternationalStandardOrganization)定义标准平衡常数SpontaneousreactionsAutomaticallyoccurredreactionswithvolumeworksonlyIrreversiblereactionsReactionshappenedwithvolumeworksornon-volumeworksEquilibriumAreactingsystemstayedbyoneselftrendstostopitsnetreactionsomewhereChemicalReactionsinaMulticomponetSystemChemicalequilibriumdealsonlywithchemicalreactionswithoutadditionalworkdoneAchemicalreactionwithelectricalworkwillbediscussedinnextchapter(Chapter10)Chemicalequilibriumandequilibriumelectrochemistry9.1TheGibbsenergyminimum9.1.1ThedefinitionofGGHTSUpVTSAPVGibbsenergyGisanextensivestatefunction,0TPdG0Spontaneous=0Equilibrium天大上册page1319.1.2ExtentofreactionForareactionas0BvBForachemicalreactionofaA+bB=cC+dDWhere:vA=-a;vB=-b;vC=c;vD=dStoichiometricnumbersvBExtentofreaction:BBdndv9.1.2ExtentofreactionForareactionas223()3()2NgHgNHInitialamount(mol)130Changeamount-0.1-0.30.2Extentofreaction:2222330.10.110.20.120.20.12NNHHNHNHdndvdnvdnv9.1.3ThereactionGibbsenergyrGdef,TPGHere∆rGisGibbsenergychangesbetweeninitialandfinalstatesbutGatrightsiderepresentstheGibbsenergyofthesystemSlopeofgraphoftheGibbsenergyplottedagainsttheextentofreactionSpontaneousEqulibriumA=BWhendT=0,dp=0,w′=0，Extentofreaction:fromξtoξ+dξBBdndGBBBd)(0',,BBwpTGpTG,)(RepresentthechangeofGwithξatasetTandpConsidertheequilibrium:A=BrmBAGEstimateGibbsenergyofreactionForareactionofperfectgases()()lnBBBpggRTP()()lnBBBggRTaForareactionofthespeciesinsolutionormixtureForapuresubstancesofliquidorsolidaB=1天大教材上：p174StandardreactionGibbsenergyWhenareactioncarriesoutatstandardstate（T，pө）,andallcomponentsinpuresubstances()mrmBfGvGBBrmBGvorrmrmrmGHTS物理化学课件下载邮箱地址：[e-mail]登录密码：１２３４５６If∆rG0Exergonicreaction(work-producing),SpontaneousreactionWorkcanbeobtainedfromanexergonicreactionItcanbeusedtodriveanotherprocess(reaction),orusedtodonon-expansionwork9.1.4ExergonicandendergonicreactionA=BIf∆rG0Endergonicreaction(work-consuming)Thereactioncanbemadetooccuronlybydoingworkonit,i.e.light,thermal,electricity.9.1.4ExergonicandendergonicreactionA=BIf∆rG=0Equilibrium,neitherexergonicnorendergonicGibbsenergyofareactingsystemPurereactantsPureproductsCombinedcurveofmixingandreactionrGdef,TPGG=GrXr+Gp(1-Xr)Gchangeofachemicalreactionwithpuresubstances∆mixGm=RT(xrlnxr+xplnxp)GchangeofamixingprocessAtkins,p166;天大上：p1859.1.5Reactionquotient:J(组成熵）Forareactionas0BvBForareactionofidealgases,Forgeneralcases,BvBppJpreactantsBvaBJaactivitiesofproductsJaactivitiesofForareactionaA+bB=cC+dDWhere:vA=-a;vB=-b;vC=c;vD=dReactionquotient:cdcdababaaJaaa9.1.6ThedirectionjudgmentofreactionsThermodynamicprincipleThepossibleprocessatconstantT,pandexpansionworksonlytendstoreduceitsGibbsenergyintominimum.Forareactionof∆rGΘ0Spontaneouschangesfrominitialtofinalstate∆rGΘ0reactionwillnothappen,butoppositereactionwillbeaspontaneousone∆rGΘ=0reactionsystemstaysatequilibrium(nonetchangeswillbeobser