In the following experiment, a coffee-cup calorimeter containing 100. \rm mL of \rm H_2O is used. The initial temperature of the calorimeter is 23.0 \rm ^{\circ}C. If 7.10g of \rm CaCl_2 is added to the calorimeter, what will be the final temperature of the solution in the calorimeter? The heat of solution, \Delta H_{\rm soln}, of \rm CaCl_2 is \rm -82.8~kJ/mol. The specific heat of water is \rm C_S=4.184~J/(g-K)