The Calculation of Fugacities from Volumetric and Phase Equilibrium Data by Means of the Gibbs-duhem Equation.
I&ec Fundamentals 1971 Aug; 10(3):428-433
Liquid and vapor fugacities, except for constants of integration, can be calculated directly, for two-component systems, from volumetric and phase equilibrium data by means of the Gibbs-Duhem equation. The constants of integration may be evaluated from the fugacities of the pure components if they exist in two-phase equilibrium at the temperature in question. Such calculations are illustrated using data on the helium-nitrogen system. Isobaric temperature derivatives of the resulting fugacity values are used in the isobaric form of the Gibbs-Duhem equation to calculate relative enthalpies of the coexisting liquid and vapor phases. These are combined with the ideal enthalpies of the mixtures to present enthalpies of the coexisting liquid and vapor phases.
I&ec Fundamentals, V. 10, No. 3, August 1971, PP. 428-433