Thermodynamics of aqueous urea solutions

Abstract

A compilation of heat capacity, heat of dilution, and activity data for aqueous urea solutions is made from published sources. The existing apparent volume data are supplemented by new measurements at 0°, 40°, and 50°. The thermodynamic data are interpreted in terms of association models, and it is found that the use of Flory-Huggins statistics for the entropy of mixing of the various associated species and the solvent gives a much better description than mole-fraction statistics. Heats of association and equilibrium constants are evaluated.