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1、物理化学()PHYSICAL CHEMISTRY（9）,过程方向和限度判据：,孤立系统,DS，熵增加原理,封闭系统,DS，熵增加原理,绝热过程,DA，赫姆霍兹函数减小原理,等温无功（等V,W=0）,DG，吉布斯函数减小原理,等温等压W0,？（有物质交换发生）,开放系统,DS，考虑环境、构建孤立系,其它过程,第三章 溶液热力学基础Thermodynamics of Multi-component Systems(Solution Chemistry),3.1 Partial molar quantities(偏摩尔量),Characteristics of multi-component and
2、 heterogeneous systems,(1)Composition and the amounts of substances are changeable in systems involving phase transitions and chemical reactions.(对其中的一相而言,可看作开放系统),Volume Change upon Mixing of C2H5OH(A)and H2O(B),wA%VA*/cm3 VB*/cm3(VA*+VB*)/cm3 V/cm3 DV/cm3 20 25.34 80.32 105.66 103.24 2.42 40 50.68
3、 60.24 110.92 106.93 3.99 60 76.02 40.16 116.18 112.22 3.96 80 101.36 20.08 121.44 118.56 2.88,(2)Nonadditivity of extensive properties,such as volume。,(3)More than 3 independent variables are needed to define the state of a system.,2.Partial molar quantities,Taking volume as an example.For a system
4、 at thermal and mechanical equilibrium,we have,Define:,as partial molar volume of substance B,Partial molar internal energy,Partial molar enthalpy,Partial molar entropy,Partial molar volumes of H2O and CH3CH2OH at 25oC,Discussion:,Partial molar quantities are intensive properties of a system.（强度性质）,
5、Perspectives of physical significance,V,xB nB,Changing rate of V against nB at a given state(T,p,and concentration xB).,偏摩尔体积也可看作是在等温等压的条件下，在无限大的系统中加入1 mol B所引起系统体积的变化量。,Conditions:Constant T and p.,For a mono-component system,3.Two important equations of partial molar quantities,(1)Additivity of pa
6、rtial molar properties(偏摩尔量的集合公式，或加和公式),在指定T，p 均不变的条件下,V是nB的一次齐函数。,根据齐函数的Euler定理,即：,(2)Gibbs-Duhem equation,At constant T and p,From,By comparison,we have,For binary systems,(A+B),VA是nA的零次齐函数，,根据齐函数的Euler定理,Or,Problem：集合公式和Gibbs-Duhem 方程的适用条件相同吗？,Similarly,We may also have,4.Determination of partial
7、 molar quantities,(1)切线法,(2)解析法,如能从实验或理论得到方程,(3)截距法,定义:,可以证明:,VA,VB,Vm,xB,0 1,3.2 Chemical potential and fundamental equations of thermodynamics for open system,1.Chemical potential,Define:,as chemical potential of component B,For closed system,dnB=0,Set:,Define:,Fundamental Equations of Chemical Thermodynamics for Open Systems(开放系统的热力学基本关系式),At a given state,Discussion:,B是强度性质,B=f(T,p,xB,),适用条件:,处于热平衡和力平衡的,没有非体积功的均相系统,Assignments,Review(XC Fu):4.14.3 Further Reading(PWA):7.17.2,Homework:Fu:Chapter 4：1，4 Atkins:Problems 7.2,
