Question

The dissociation of a salt in water to from an aqueous solution is called enthalpy of solution, ΔHsoln. The ΔHsoln for CaCl2 is -120 kJ/mol. When CaCl2 is added to water _____. A) the temperature of the water will increase. B) the temperature of the water will remain the same. C) the process is endothermic. D)nothing will occur, CaCl2 is insoluble.

Answer 1

Answer:

A) the temperature of the water will increase.

Explanation:

Consider, first, the dissolution of anhydrous calcium chloride, CaCl2 in water. CaCl2 is a very water soluble ionic compound that, in solution, dissociates into the component ions, Ca2 + and Cl-, which interact strongly with water molecules.

The thermochemical equation that represents the process of dissolution of CaCl2 (s) indicates that it is a strongly exothermic process:

CaCl2(s) --> Ca+2(aq) + 2Cl- (aq)   ΔH = -82.8 kJ

Therefore, dissolving CaCl2 in water will produce the release of energy in the form of heat (82.8 kJ per mole of dissolved CaCl2)