Molar volumes and heat capacities of electrolytes and ions in nonaqueous solvents: 1. Formamide

Abstract

Apparent molar volumes and heat capacities of 27 electrolytes have been measured as a function of concn. in formamide at 25°C using a series-connected flow densimeter and Picker calorimeter system. These data were extrapolated to infinite diln. using the appropriate Debye-Huckel limiting slopes to give the corresponding std. partial molar quantities. Ionic vols. and heat capacities at infinite diln. were obtained by an appropriate assumption based on the ref. electrolyte Ph4PBPh4 (TPTB). The ionic vols., but not the heat capacities. agree reasonably well with previously published statistically based predictions. The values obtained are discussed in terms of simple models of electrolyte soln. behavior and a no. of interesting features are noted, including, possible dependencies of ionic vols. on solvent isothermal compressibility and of ionic heat capacities on solvent electron acceptor abilities.