15:48:33 例子续2 S.J.T.U. Phase Transformation and Applications Page 6/46 若上述转移过程可以实现，则 0相 β相 dG=(uu)(dng)< 因为dng>0 所以 4g<4g 组分B有dn由o相 进入B相 上式表明物质总是由化学势较高的相自发转移到化学势较 低的相，直到该物质在两相中的化学势相等。 对比水与水位、电流与电势的关系，也有某种势的意思， 所以称为化学势 SJTU Thermodynamics of Materials Spring2007©X.J.Jin Lecture 12 Solution Il
Phase Transformation and Applications S. J. T. U. SJTU Thermodynamics of Materials Spring 2007 © X. J. Jin Lecture 12 Solution II Page 6/46 15:48:33 例子续2 上式表明物质总是由化学势较高的相自发转移到化学势较 低的相，直到该物质在两相中的化学势相等。 对比水与水位、电流与电势的关系，也有某种“势”的意思， 所以称为化学势 若上述转移过程可以实现，则 −= < 0))(( dG dnBBB αβ μμ 因为 所以 dnB > 0 αβ < μμ BB 组分B有dnB由α相 进入β相 α相 β相
15:48:33 化学势判据 S.J.T.U. Phase Transformation and Applications Page 7/46 ∑4sdnB≤0 ∑4，d,≤0 这一判据式讨论具体的平衡规律、过程的方向与限度 SJTU Thermodynamics of Materials Spring2007©X.J.Jin Lecture 12 Solution Il
Phase Transformation and Applications S. J. T. U. SJTU Thermodynamics of Materials Spring 2007 © X. J. Jin Lecture 12 Solution II Page 7/46 15:48:33 这一判据式讨论具体的平衡规律、过程的方向与限度 ∑ ≤ 0 B μ dnBB 化学势判据 ∑ ≤ 0 i ii μ dn
15:48:33 P,V,Xi影响化学势 S.J.T.U. Phase Transformation and Applications Page 8/46 1,温度的影响 ∂G 29R =-S OT) ,xi 2,压力的影响 气相 aG RT =V L= dG=RTdln P aP P T,xi 3,组成的影响：偏摩尔Gibbs自由能 SJTU Thermodynamics of Materials Spring 2007 ©X.J.Jin Lecture 12 Solution Il
Phase Transformation and Applications S. J. T. U. SJTU Thermodynamics of Materials Spring 2007 © X. J. Jin Lecture 12 Solution II Page 8/46 15:48:33 P, V, Xi影响化学势 S T G i xP ⎟ −= ⎠⎞ ⎜⎝⎛ ∂∂ , dT TC S P ∫ = 2980 0298 1，温度的影响 2，压力的影响 V P G i xT ⎟ = ⎠⎞ ⎜⎝⎛ ∂∂ , PRT V = 气相 = ln PRTdGd 3，组成的影响：偏摩尔Gibbs自由能
15:48:33 Thermodynamic activity S.J.T.U. Phase Transformation and Applications Page 9/46 Fugacity is defined for gases: dGi =RTd(Inf) Thermodynamic activity of a component,i,is defined as: The fugacity of the componentiin its standard state. The fugacity of a condensed phase is equal to the fugacity of the vapor phase in equilibrium with it. The fugacity of the vapor is equal to the pressure of the vapor,if the vapor in equilibrium with the condensed phase is ideal. SJTU Thermodynamics of Materials Spring2007©X.J.Jin Lecture 12 Solution Il
Phase Transformation and Applications S. J. T. U. SJTU Thermodynamics of Materials Spring 2007 © X. J. Jin Lecture 12 Solution II Page 9/46 15:48:33 )(ln i i = fRTdGd o i i i f f α ≡ Thermodynamic activity Fugacity is defined for gases: Thermodynamic activity of a component, i, is defined as: o i f The fugacity of the component i in its standard state. The fugacity of a condensed phase is equal to the fugacity of the vapor phase in equilibrium with it. The fugacity of the vapor is equal to the pressure of the vapor, if the vapor in equilibrium with the condensed phase is ideal
15:48:33 Relative Partial Molar Quantities S.J.T.U. Phase Transformation and Applications Page 10/46 Mixing of A and B to form a solution,the volume changes: AVmixing =VM =Vfimal -Vimitial VM is the volume change upon mixing: 混合前后容量性质变化 Vy =naVA+nBV B-naLa-nBLB Vy=na(VA-La)-nB(VB-LB) 网A-卫 The relative partial molar volume of A The partial molar volume of A in solution relative to the molar volume of pure A. -rel rel Vy =navA +nBVB SJTU Thermodynamics of Materials Spring2007©X.J.Jin Lecture 12 Solution Il
Phase Transformation and Applications S. J. T. U. SJTU Thermodynamics of Materials Spring 2007 © X. J. Jin Lecture 12 Solution II Page 10/46 15:48:33 Relative Partial Molar Quantities Δ mixing M == final −VVVV initial AM A B B A A BVnVnVnVnV B −−+= )()( AM A A B B VVnVVnV B −−−= rel B B rel AM A += VnVnV Mixing of A and B to form a solution, the volume changes: VM is the volume change upon mixing: A A −VV The relative partial molar volume of A The partial molar volume of A in solution relative to the molar volume of pure A. rel V A 混合前后容量性质变化