Energy released from changing the phase of a substance from the gas phase to liquid phase can be calculated by using the specific latent heat of vaporization. The heat of fusion of water at 0 degrees Celsius is 40.7 kJ/mol. Calculation are as follows:
Energy = 27.9 g (1 mol / 18.02 g) x 40.7 kJ/mol
Energy = 63.09 kJ
