Chapter 9: thermodynamic criteria between phases
Let’s imagine a system with two phases, liquid and vapor, in order to be in equilibrium, it has to obey the following statements.
Chemical potential (μ) is not usually used to explain equilibrium in a system but fugacity in terms of Gibbs Free Energy can explain the tendency to one of the two phases or if the system is in equilibrium.
With this equation we can determine if the system is in equilibrium, calculating the fugacity of both phases. Let’s take the last example of system with two phases; liquid and vapor. If the fugacity is equal in both phases then the system is in equilibrium.
If the fugacity of the liquid phase is less than the fugacity of the vapor phase, then the system tends to the liquid phase.
If the fugacity of the vapor phase is less than the fugacity of the liquid phase, the system tends to the vapor phase.
We can conclude that the phase with less fugacity determines the behavior of the system.
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phaseequil2.pdf | |
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Paper got from: H. Monica-UNAM. equilibria between phases http://www.cie.unam.mx/~mlh/documentos/Miguel/phaseequil2.pdf
References: UTN – Facultad Regional Rosario. Propiedades Termodinámicas de Equilibrio. Determinación de estado de equilibrio de fases. Recuperado de http://www.modeladoeningenieria.edu.ar/mei/repositorio/catedras/intIV/apuntes/apunte_prop_termodinamicas.pdf
References: UTN – Facultad Regional Rosario. Propiedades Termodinámicas de Equilibrio. Determinación de estado de equilibrio de fases. Recuperado de http://www.modeladoeningenieria.edu.ar/mei/repositorio/catedras/intIV/apuntes/apunte_prop_termodinamicas.pdf