Heat capacities of concentrated multicomponent aqueous electrolyte solutions at various temperatures

Abstract

The specific heat capacities of the aqueous multicomponent system NaCl +KCl+MgCl2+CaCl2 with ionic strength between 8.3 and 9.6 (resembling Dead Sea waters) were measured between 15°C and 45°C. The obtained data were fitted to an empirical equation as a function of concentration and temperature. The thermodynamic functions of the studied multicomponent system were found to be strongly influenced by changes in MgCl2 concentrations. The application of Young's rule to such concentrated systems was checked at 25°C. The calculated (by Young's rule) specific heat capacitiesCp and apparent molar heat capacities Cp,ϕ of these multicomponent electrolyte solutions were in reasonable agreement with the measured values (−0.008 J-g−1-K−1 and −2.6 J-mol−1-K−1, respectively).