Apparent molal volumes and heat capacities of some 1:1 electrolytes in anhydrous methanol at 25�C

Abstract

A flow calorimeter and flow densimeter have been used to measure volume specific heats and densities of solutions of LiCl, LiBr, NaCl, NaBr, KF, KBr, Kl, CsF, and Bu4NBr in anhydrous methanol at 25°C. The concentrations ranged from approximately 0.01m to close to saturation in some cases. Apparent molal heat capacities φ cp and volumes φ v have been evaluated and extrapolated to infinite dilution to obtain φ and φ . Nearly all the heat capacities in methanol are negative. However, with the exception of the lithium halides and Bu4NBr they are more positive than heat capacities of the corresponding salts in water. The dependence of the heat capacities on ionic radii is generally opposite in methanol solutions from that observed for aqueous solutions. In agreement with others, the φ data indicate that electrostriction in methanol solutions is greater than in aqueous solutions.