A coffee cup calorimeter initially contains 125 g of water, at a temperature of 24.2° C, 8 g of ammonium nitrate $\left({\mathrm{NH}}_4{\mathrm{NO}}_3\right)$, also at 24.2° C, is added to the water, and the final temperature is 18.2° C, what is the heat of solution of ammonium nitrate in kJ/mol? (The specific heat capacity of the solution is 4.2 J/°C.)