Question: how to calculate how much heat is released?
Answer: Calculate the heat released, q, in joules (J), by the reaction: q = mass(water) × specific heat capacity(water) × change in temperature(solution) ... 
Calculate the moles of solute (NaOH(s)): moles = mass ÷ molar mass. ... 
Calculate the enthalpy change, ΔH, in kJ mol-1 of solute: