Sports Trainers Use Cold Packs Containing Ammonium Nitrate for Injured $\circ$

Sports trainers use cold packs containing ammonium nitrate for injured athletes. Calculate the change in temperature when 47 g of ammonium nitrate (NH₄NO₃, 80.1 g/mol) dissolves in 100 g water. Assume the specific heat of the solution is 4.5 J/(g . ^$\circ$ C).
NH₄NO₃(s) NH₄⁺(aq) NO₃^-(aq) $~~~~~~~~$$\Delta$ H = 21.1 kJ/mol