endothermic exothermic reaction

 For Part II, find ΔHrxn (in units of kJ/mol of NaOH) using q = mCsΔT. Recall, that you measured the change in the temperature of the entire system in the calorimeter, so be careful what value you use for “m” (big hint: assume the combined solution has a density of 1 g/mL and use the combined volumes of the two solutions to calculate the mass of the combined solution). Use Cs for water (4.184 J/g C). The above equation allows you to find q. But in order to find ΔHrxn (in units of kJ/mol of NaOH) you must divide q by the total number of moles of NaOH you used (you know the volume of NaOH, and the molarity, from the experiment). You must also divide by 1000 to report as KJ/mol rather than J.