On the correlation of the excess surface heat capacity and the surface molar volume of liquid

Abstract

Excess surface heat capacity values [Formula: see text] have been calculated using several surface density models. It is expected that calaculated [Formula: see text] values would be negative to be thermodynamically consistent. Using bulk liquid volume data as a means of calculating first estimates of surface volumes yields positive [Formula: see text] for a group of compounds of wide polarity. However, a simple linear or non-linear surface density model relating bulk density to surface density and reduced temperatures has been shown to yield negative values of [Formula: see text] This new surface density model is applicable to both polar and non-polar compounds and thus should prove useful for calculating molar surface areas for polar compounds which are necessary for calculating the surface tensions of polar–polar liquid mixtures. Keywords: excess surface heat capacity, surface density, monolayer model.