Nickel Sulfate Aqueous Solutions Thermal Chemistry and Enthalpy of Ni2+ Cation Formation at the Temperature 298.15 K

Calorimeter with an isothermal shell was used at a temperature of 298.15 K to measure the following parameters: enthalpy of NiSO4(k) dissolution in water followed by generation of two molar concentration solutions; enthalpy of four NiSO4 aqueous solutions dilution having various molar concentrations followed by generation of solutions with approximately the same concentration values. Based on the data obtained, enthalpy and ion association constant in the NiSO4 aqueous solution, as well as standard enthalpy of the aqueous solution formation, were determined for the indicated compound. The latter value made it possible to establish a more accurate value of standard enthalpy in the Ni2+ cation formation in an aqueous solution, which turned out to be equal to --52.3 ± 0.5 kJ/mol.