Alkali metal and ammonium chlorides in water + urea systems ΔG, ΔH, ΔS of transfer from water to mixtures containing up to 40 % urea

Abstract

Enthalpies, Gibbs free energies and entropies of transfer from water to water + urea mixtures for LiCl, NaCl, KCl, RbCl, CsCl and NH4Cl are reported. Gibbs free energies are obtained using glass electrodes sensitive to alkali cations and enthalpies of transfer are calculated from calorimetric measurements of the enthalpies of solution. Data thus obtained are discussed in terms of the various models of the water + urea mixtures. It is suggested that the properties of solutes are mainly related to the properties of water in the same mixture.