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Solution: Estimate the heat of solution of CaCl₂.

lattice energy of solid CaCl₂: +2258 kJ mol^–1

hydration energy of the three gaseous ions: (–1562 –381 – 381) = –2324 kJ mol^–1

heat of solution: (2258 – 2324) kJ mol^–1 = –66 kJ mol^–1

Since the process is exothermic, this amount of heat will be released, warming the solution.