Molar volumes and heat capacities of aqueous solutions of Mg(ClO₄)₂

Densities and isobaric heat capacities of about 25 aqueous solutions of magnesium perchlorate, Mg(ClO₄)₂(aq), have been measured at concentrations 0.01 ≲ m/mol· kg^-1 ≲ 2.5 using vibrating tube densimetry and flow calorimetry, respectively. Densities were determined at temperatures from 293.15 to 343.15 at 5 K intervals, but heat capacities were restricted to 298.15 K. These data were used to calculate the corresponding apparent molar volumes, V_ϕ, and isobaric heat capacities, C_pϕ, which were extrapolated to infinite dilution using appropriate semi-empirical equations to give the standard-state values, V° and C_p°. Where comparisons were possible, the present results are in good agreement with literature data but are more extensive and precise. Standard values for Mg ⁺(aq) were obtained using appropriate extrathermodynamic assumptions and also agreed well with literature estimates. Unlike many inorganic salts, the V° values for Mg(ClO₄)₂(aq) do not show a maximum over the investigated temperature range.