Lecture28A - Lecture 28 Thermodynamic Equilibrium...

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Lecture 28 1 Lecture 28 - Thermodynamic Equilibrium Constant (26.11-12) In the previous lecture, we introduced a thermodynamic equilibrium constant based on fugacities: where and Y Z Y Z Y Z A B A B A B v v v v v v Y Z Y Z Y Z f P P v v v v v v A B A B A B f f P P K K K K K f f P P Remember, the physical observable we measure is pressure, but the equilibrium constant is based on fugacities. We need a more general relation to cover not only gases, but liquids, solids and solutions (i.e. multicomponent, multiphase, reacting systems!) We need to start somewhere…so let’s begin with our basic definitions. We’ve got liquids and solutions down pat:   ln activity of component . o j j j j T RT a a j For solutions with solvent and solute this is well-defined: as 1 Raoult's law Standard State , as , 0 Henry's law Standard State j j j j j j j j a x x a c m c m

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2 We can readily extend this form for gases by letting where fugacity of component . j j o j i f a f f j For arbitrary states and phases for reactants and products: A B Y Z v A v B v Y v Z ± ln where Y Z A B v v o Y Z r Y Y Z Z A A B B r v v A B o o o o o r Y Y Z Z A A B B a a G v v v v G RT a a G v v v v   th century giants of thermodynamics. They wrote the classic thermodynamics text book used by generations. Again as before: Y Z A B v v Y Z a v v A B a a Q a a a G G  
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This note was uploaded on 04/13/2008 for the course CHEM 444 taught by Professor Jameslis during the Spring '08 term at University of Illinois at Urbana–Champaign.

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Lecture28A - Lecture 28 Thermodynamic Equilibrium...

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