Calculation of Heat Capacities and Compressibilities of Liquids from a Rigid Sphere Equation of State

Abstract

Equations for heat capacities and compressibilities of liquids were calculated by differentiation of the expression for the entropy of a fluid of rigid spheres. The resulting equations contain no adjustable parameters. The information required in addition to the heat capacity and compressibility of the gas, is the diameter of the molecule, the liquid density and its variation with temperature. The equations were applied to the rare gases and to diatomic and polyatomic molecules at their boiling points. Agreement between the calculated and observed values was with few exceptions very good. Further, the calculated temperature dependence showed good agreement with experimental values.