Chapter 9, Problem 25E

Dissolving 3.0 g of CaCl₂(s) in 150.0 g of water in a calorimeter (Figure 9.12) at 22.4 °C causes the temperature to rise to 25.8 °C. What is the approximate amount of heat involved in the dissolution, assuming the specific heat of the resulting solution is 4.18 J/g °C? Is the reaction exothermic or endothermic?

Figure 9.12 A simple calorimeter can be constructed from two polystyrene cups. A the mometer and stirrer extend through the cover into the reaction mixture.