A calorimeter contains 32.0 of water at 12.0. When 2.10 of (a substance with a molar mass of 63.0 ) is added, it dissolves via the reaction
X(s)+H2O(l) -> X(aq)
and the temperature of the solution increases to 26.5. Calculate the enthalpy change,for this reaction per mole of X.
Assume that the specific heat and density of the resulting solution are equal to those of water [4.18J/g*C and 1.00g/mL ] and that no heat is lost to the calorimeter itself, nor to the surroundings.