A calorimeter contains 35.0 mL of water at 15.0 degrees Celsius. When 2.30 g of (a substance with a molar mass of 49.0 g/mol ) is added, it dissolves via the reaction: and the temperature of the solution increases to 30.0 degrees Celsius. Calculate the enthalpy change, ΔH, for this reaction per mole of X. Assume that the specific heat and density of the resulting solution are equal to those of water (4.18 J/(g degree Celsius) and 1.00 g/mL) and that no heat is lost to the calorimeter itself, nor to the surroundings. (Express the change in enthalpy in kilojoules per mole to three significant figures.)
X(s) + H2O(l) → X(aq)