Calculating models of mass action concentrations for structural units or ion couples in RbCl-H 2O binary system and RbCl-RbNO 3-H 2O ternary system

Abstract

Thermodynamic models of calculating mass action concentrations for structural units or ion couples in RbCl-H 2O binary and RbCl-RbNO 3-H 2O ternary strong electrolyte aqueous solutions were developed based on the ion and molecule coexistence theory at 298.15 K. A transformation coefficient is needed to compare the calculated mass action concentration and the reported activity because they are obtained at different standard states and concentration units. The results show that the transformation coefficients between the calculated mass action concentrations and the reported activities of the same structural units or ion couples in RbCl-H 2O binary and RbCl-RbNO 3-H 2O ternary strong electrolyte aqueous solutions change in a very narrow range. The transformed mass action concentrations of structural units or ion couples in RbCl-H 2O binary system are in good agreement with the reported activities. The transformed mass action concentrations of RbCl and RbNO 3 in RbCl-RbNO 3-H 2O ternary solution are also in good agreement with the reported activities, a RbCl and, with different total ionic strengths as 0.01, 0.05, 0.1, 0.5, 1.0, 1.5, 2.0, 3.0 and 3.5 mol/kg, respectively. All those results mean the developed thermodynamic model of strong electrolyte aqueous solutions can reflect structural characteristics of RbCl-H 2O binary and RbCl-RbNO 3-H 2O ternary strong electrolyte aqueous solutions and the mass action concentration also strictly follows the mass action law.