超额性质本身是衡量溶液非理想性的程度.PPT

7.4 Fugacity Fugacity Coefficient 7.4.1 Definition At constant temperature, 1 mole pure fluid i: For Ideal-Gas: For Practical-Gas: Fugacity of pure composition i, ……………………………Part I For Ideal-Gas: …………………………………………Part II Definition for Composition i in the Mixture －Partial-Molar Free Enthalpy for 1 mole Mixture －Fugacity of composition i －Molar Fraction of composition i －Pressure of Mixture Definition for Mixture －Molar Free Enthalpy for 1 mole Mixture －Fugacity of Mixture －Pressure of Mixture Fugacity Coefficient For pure substance For composition i of mixture For mixture 7.4.2 Fugacity Evaluation of Pure Gas Evaluation on Experimental Data ……(1) ……(2) (1)+(2): (1) From pVT data Relationship between Residual Volume and Compressible Factor (2) From Enthalpy and Entropy data Integrated to: *－Base Parameter 基准态参数 Evaluation on Generalized Relationship (1) Generalized Virial Coefficient (2) Generalized Compressible Factor 7.4.3 Fugacity Evaluation of Pure Liquid 液体的逸度可以看成分子由液相向气体逃逸的程度。 For single composition, when balanced: －Fugacity of Saturate Vapor or Saturate Liquid －Fugacity Coefficient of pure liquid at T and Saturate Vapor Pressure Integrated to (Saturate at T to Liquid at p): Pointing Factor 7.4.4 Fugacity Evaluation of Gas Mixture 7.4.4 Pressure Temperature Effect on Fugacity Mixture Pure Substance Mixture Pure Substance Temperature Pressure 7.5 Weak Solution 7.5.1 Renoult’s Law The relationship between pressure of solvent and its molar fraction is: The saturated pressure of solvent in weak solution equals the production of saturated pressure of solvent in the same temperature and its molar fraction. The decreased fraction in vapor pressure of solution equals the molar fraction of solute. Molar Fraction of Solute 7.5.2 Henry’s Law Under given temperature and equilibrium the molar fraction of gas in liquid is proportional to the gas pressure above the surface of liquid －Molar fraction of solute (gas) in solvent (liquid) －Gas pressure above the surface of