7 Solution Thermodynamics & Phase EquilibriumObjective:· Basic conceptions of solution thermodynamics·Evaluation of Fugacity Coefficient and Activity Coefficient· Basic conceptions , principles and diaphragm of weaksolution ,ideal solution and non-ideal solution· Basic conceptions of gas-liquid phase equilibrium and itsevaluation
7 Solution Thermodynamics & Phase Equilibrium Objective: • Basic conceptions of solution thermodynamics • Evaluation of Fugacity Coefficient and Activity Coefficient • Basic conceptions , principles and diaphragm of weak solution ,ideal solution and non-ideal solution • Basic conceptions of gas-liquid phase equilibrium and its evaluation
7.1 Free Energy and Free Enthalpy7.1.1 Free EnergyConstant temperature + volumeclosedsystemConstant temperature + pressureEnergy transfer with surroundings1st Law of ThermodynamicsdU =Q-8WtotTotal Work ofReversibleProcessSystemdU = QRey -SWtotRevNon-expansionSWrorRev = pdV +#WWorkeRev
7.1 Free Energy and Free Enthalpy 7.1.1 Free Energy closed system Constant temperature + volume Constant temperature + pressure Energy transfer with surroundings 1 st Law of Thermodynamics d δ δ U Q W = − tot Reversible Process Rev Rev Rev Rev d δ δ δ d δ tot tot e U Q W W p V W = − = + Total Work of System Non-expansion Work
SQReydsSQRev,=TdS-TdU =TdS-pdV-SWeRevConstant temperature + volumedU = d(TS)-SWeRevU-TS=-8WeRevA=U-TSHelmholtzfreeenergy
Rev δ d Q S T = Rev d d d δ U T S p V W = − − e Rev δQ T S = d Constant temperature + volume Rev Rev d d( ) δ d( ) δ = − − = − e e U TS W U TS W A U TS = − Helmholtz free energy
Ais a State Property, so...物系的状态一定，则有确定的A值ii只要始终状态一定，则不论过程是否恒温恒容或是可逆A其为一定值。AA = △U - △(TS)ii只有在恒温恒容可逆过程中A才等于物系所做的最大非体积体积功。-Ar = WeRev自由能的减少等于物系所做的最大非体积功Constant temperature:T = T, = Tsuroundings == Constant
A is a State Property, so. i 物系的状态一定，则有确定的A值 ii 只要始终状态一定，则不论过程是否恒温恒容 或是可逆，其 为一定值。 iii 只有在恒温恒容可逆过程中， 才等于物系所 做的最大非体积体积功。 自由能的减少等于物系所做的最大非体积功。 A = − A U TS ( ) A − = A W T V e , Rev Constant temperature: 1 2 Constant T T T = = = Surroundings
Free Energy Criterion<0AATSpontaneous△Arv = 0EquilibriumImpossible△AT >0
Free Energy Criterion , 0 AT V, 0 AT V, 0 = AT V Spontaneous Equilibrium Impossible