Question

Given that the heat of fusion of water is +6.02 kJ/mol, that the heat capacity of H2O(l) is 75.2 J/mol⋅K and that the heat capacity of H2O(s) is 37.7 J/mol⋅K, calculate the heat of fusion of water at -15 ∘C. Express your answer using two significant figures.

deltaH= ___?____ kJ/mol

Answer 1

heat capacity of H2O(l) = 75.2 J/mol⋅K   = 0.0752 kJ/ mol.K

heat capacity of H2O(s) = 37.7 J/mol⋅K = 0.0377 kJ/ mol K

heat of fusion = -6.02 kJ / mole ( liquid to solid heat releases ) it is at 0oC

at -15 ∘C   heat of fusion = -6.02 - (-15 x (0.0752 -0.0377 ))

                                         = -6.02 + 0.5625

                                           = -5.46 kJ

heat of fusion of water at -15^∘C = - 5.5 kJ