Molecular Thermodynamics of Fluid-Phase Equilibria

Chapter 3 Thermodynamic Properties from Volumetric Data

For any substance, regardless of whether it is pure or a mixture, most thermodynamic properties of interest in phase equilibria can be calculated from thermal and volumetric measurements. For a given phase (solid, liquid, or gas), thermal measurements (heat capacities) give information on how some thermodynamic properties vary with temperature, whereas volumetric measurements give information on how thermodynamic properties vary with pressure or density at constant temperature. Whenever there is a change of phase (e.g., fusion or vaporization), additional thermal and volumetric measurements are required to characterize that change.

Frequently, it is useful to express a selected thermodynamic ...