Water Properties: Vaporization Heat vs. Temperature Charts and Calculator Delta Vap H Latent Heat of Vaporization Delta Hvap of Water calculated by corresponding states correlation in a one cell excel formula Standard enthalpy of vaporization (vapH) for water at 100C is 40.66 kJ.. 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 Standard enthalpy of vaporisation`DeltaV_(vap).H^(Theta)` for water at `100^(@)C`is`40.66kJmol^( 1)`.Teh internal energy of Vaporization of water at` 100^(@)C("in kJ mol"^( 1))`is