Consider the dissolution of CaCl2.?

Question

Consider the dissolution of CaCl2.
CaCl2(s) Ca2+(aq) + 2 Cl -(aq) H = -81.5 kJ

A 11.9 g sample of CaCl2 is dissolved in 119 g of water, with both substances at 25.0°C. Calculate the final temperature of the solution assuming no heat lost to the surroundings and assuming the solution has a specific heat capacity of 4.18 J/°C·g.

Answer 1

The molar mass of anhydrous CaCl2 is 110.99 g/mol.
11.9 g CaCl2 in 119g water <==> 0.107 mol CaCl2 in 131g solution <==> 8.74 kJ heat to heat up the solution ==> temperature increase = (8.74 kJ)/(131g*4.18 J/°C·g) = 16.0°C. Thus the final temperature of the solution is 41.0°C.