Phase Transitions (10.3) Chemistry 110 Video answer for \Delta_{\text {vap }} \mathrm{H}^{\Theta} for water is +40.79 \mathrm{kJ} \mathrm{mol}^{ 1} at 1 bar and 100^{\circ} \mathrm{C}. Change in internal energy for this vapourisation under Predicting the Enthalpy of Vaporization and Calculating the Entropy of Vaporization of 87 Octane Gasoline Using Vapor Pressure Water Properties: Vaporization Heat vs. Temperature Charts and Calculator Delta H^0 vap of water is +40.79 kJ mol at 1 bar and 100 deg C. Change in internal energy for this__