Solved Hvap = heat of vaporization = constant R= gas Chegg.com Standard enthalpy of vapourisation \Delta _ { \mathrm { vap } } \mathrm {.. Buzztutor Questions and Answers by Category Vaporization enthalpy of isooctane (2,2,4 trimethylpentane). The fitted Download Scientific Diagram Delta_{vap}H^ for water is +40.49 kJ moi^ 1 at 1 bar and 100C . Change in internal energy for this vaporization under same condition is Sarthaks eConnect Largest Online Education Community