Two Solutions, Initially at 24

Two solutions, initially at 24.69 °C, are mixed in a coffee cup calorimeter (C_cal = 105.5 J °C^-1) . When a 200.0 mL volume of 0.100 mol L^-1 AgNO₃ solution is mixed with a 100.0 mL sample of 0.100 mol L^-1 NaCl solution, the temperature in the calorimeter rises to 25.16 °C. Determine the Δ_rH°, in units of kJ mol^-1. Assume that the density and heat capacity of the solutions is the same as that of water. Hint: Write a balanced reaction for the process.

A) -32 kJ mol^-1
B) -78 kJ mol^-1
C) -64 kJ mol^-1
D) -25 kJ mol^-1
E) -52 kJ mol^-1