In a coffee-cup calorimeter, 1.60g of NH4NO3 is mixed with 75.0g of water at an initial temperature of 25.00 degrees Celsius. After dissolution of the salt, the final temperature of the calorimeter contents is 23.34 degrees Celsius. Assuming the solution has a heat capacity 0f 4.18 J/g * degrees Celsius and assuming no heat loss to the calorimeter, calculate the enthalpy change for the dissolution of NH4NO3 in units of kJ/mol.


Not sure how to do this please help.

enthalpy change  = mass of the solution X specific of the water X increase in temp