Integral heats of solution for CU(II) halides in water at 23 ± 1₋p0₋sC.

Abstract

Integral heats of solution have been measured at constant pressure as a function of concentration for copper(II} chloride dihydrate, copper(II} chloride, and copper(II} bromide in water at 23 ± lOC, by the method of solution calorimetry. The heat of solution at infinite dilution for each halide is obtained graphically by linear extrapolation of enthalpy vs. m1/ 2 curves. Data for CUC1 2 compare well with enthalpy data in the literature; CUC1 2 results are also in excellent agreement with temperature derivatives of activity and osmotic coefficient data from the literature. the two sets of data being correlated via the relative apparent molal enthalpy. Dissolution of copper(II} halides in water at room temperature is an exothermic process. The enthalpy of solution decreases in absolute value with: 1} an increase in the waters of hydration of the crystalline salt; and. 2) a decrease in anionic charge density.