posted by Ellen .
A calorimeter contains 21.0 mL of water at 14.0 degreesC. When 1.90 g of X (a substance with a molar mass of 70.0 g/mol) is added, it dissolves via the reaction
X(s)+H_2O(l)reacts to make X(aq)
and the temperature of the solution increases to 28.5degreesC.
Calculate the enthalpy change, Delta H, 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/degrees C) and 1.0g/mL] and that no heat is lost to the calorimeter itself, nor to the surroundings.