A student places 6.50 g of solid NH4NO3 into 125.0 g of water in a perfectly insulated coffee-cup calorimeter. The water is initially at 24.6 °C; once the salt has completely dissolved, the final temperature of the solution is 19.4 °C. Assume the specific heat capacity of the solution is the same as that of water.
(a) Determine the quantity of heat associated with the temperature change of the solution. Include the correct sign.
(b) Calculate the number of moles of NH4NO3 dissolved.
(c) Determine the molar enthalpy change, ΔHdissolution, for NH4NO3 based on the student’s data. Report your answer with appropriate sign and units.