For water vap H = 41 kJ mol^1 at 373 K and 1 bar pressure. Assuming that water vapour Sarthaks eConnect Largest Online Education Community 10.10: Enthalpy of Fusion and Enthalpy of Vaporization Chemistry LibreTexts Determine the standard enthalpy of formation of water at 650 Hvap for water is 40.7 KJ `mol^(1)` . The entropy of vaporization of water is: The enthalpy of vapourisation of liquid water using the data : `H_(2)(g)+1 2O_(2)(g)rarr H_(2)O(l) Heats of Vaporization and Condensation Examples, Calculations and Definitions CK 12 Foundation