in the following experiment a constant-pressure

Question

In the following experiment, a constant-pressure calorimeter containing 100 ml of H₂O is used. The initial temperature of the calorimeter is 24.6^oC. If 18.6g of CaCl₂is added to the calorimeter, what will be the final temperature of the solution in the calorimeter? The heat of solution of CaCl₂is  -82.8 kJ/mol.
The specific heat of water is C_s = 4.18 J g^-1 K^-1.