Introduction to Chemical Engineering
Thermodynamics
Chapter 6
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Relations for homogeneous fluid of constant composition
Helmholtz energyA=U-TS
Gibbs energyG=H-TS
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Total differential of F:
the order of differentiationof an analytic function oftwo variables is irrelevant
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Maxwell’s Equations
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Enthalpy and Entropy as functions of T & P
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Case of an ideal gas
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Volume expansivity
Isothermal compressibility
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Alternative form for liquids
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Internal Energy and Entropy as function of T & V
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Alternative forms:
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Gibbs Energy as a Generating Function
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If given G/RT=g(T,P) thenone can evaluate all other thermodynamic properties:
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Residual Properties
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for constant T
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J arbitrarily set equal to 0
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Enthalpy and Entropy from HR and SR
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Residual Properties from the Virial EOS
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Residual Properties by EOS
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Residual Properties by three-term virial equation
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Residual Properties by Cubic EOS
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Two phases α and β of a pure species coexisting at equilibrium
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Clapeyron equation
for an ideal gas
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T-dependence of vapor pressure
Wagner equation:
Antoine equation:
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Lee and Kesler Pitzer-type correlation
for non-polar & non-associating liquids
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Two-Phase Liquid-Vapor Systems
quality
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Lee Kesler correlationSee Appendix E
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At low pressure for non polar and non associating molecules, onecan use the generalized second-virial-coefficient correlation:
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