Question

A calorimeter contains 32.0mL of water at 12.5 degrees celcius.When 2.30g of X (a substance with a molar mass of 66.0 g/mol ) isadded, it dissolves via the reaction: X(s) +H2O(l)--->X(aq)

and the temperature of the solution increases to 26.5 degreescelcius.
Calculate the enthalpy change, Delta H, for this reaction per moleof X.

Assume that the specific heat and density of the resulting solutionare equal to those of water [4.18 J/(g*degree celcius) and 1.00g/mL] and that no heat is lost to the calorimeter itself, nor tothe surroundings.

Express the change in enthalpy in kilojoules per mole to threesignificant figures.