Part A: A calorimeter contains 18.0 mL of water at 13.5∘C. When
2.30 g of X (a substance with a molar mass of 69.0 g/mol) is added,
it dissolves via the reaction X(s)+H2O(l)→X(aq) and the temperature
of the solution increases to 30.0∘C. Calculate the enthalpy change,
ΔH, for this reaction per mole of X. Assume that the specific heat
of the resulting solution is equal to that of water [4.18
J/(g⋅∘C)], that density of water is 1.00 g/mL, and that...