Question

there's a 5.44 g sample of NH4NO3 and 150 g sample of water. So they ask for the change in enthalpy in kJ/mol. They give the temperature change from 16.2 degrees C to 18.6 degrees C. They also provide the specific heat capacity of the entire solution (155.4g) as 4.2 J/g*K. How do you solve for the change in enthalpy?? I kept getting the wrong answer. I thought you had to just use the equation q = mc*(change in temperature)