F5 Chem calculation

In an experiment, 10 g of KCl(s) was added to 100 cm³ of water. The mixture was thenstirred until all the KCl(s) dissolved. The temperature of the mixture was foundto drop by 5.5 degree Celsius. What is the molar enthalpy change, in kJmol⁻¹, of the dissolving processof KCl(s) under the conditions of the experiment?
( Specific heat capacity ofthe mixture = 4.2 kg⁻¹ K⁻¹; Density of water =1.0 gcm⁻¹; Relative atomic masses: K= 39.1, Cl = 35.5)


Note that the specific heat capacity of the mixture should be 4.2 kJ kg⁻¹ K⁻¹ or 4.2 J g⁻¹ K⁻¹.

Mass of the solution, m = 100 x 1.0 + 10 = 110 g =0.11 kg
Heat absorbed = m c ΔT = 0.11 x 4.2 x 5.5 = 2.541kJ
No. of moles of KCl used = 10/(39.1 + 35.5) = 0.134 mol
Molar enthalpy change = 2.541/0.134 = 18.96 kJ mol⁻¹