Chloroform has \Delta \mathrm { H } _ { \text {vaporization } } = 29.2 \m.. Heat of Vaporization from Vapor Pressure (Example) 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 Vapour Pressure vs 1 T Delta Hvap Clausius Chegg.com If \Delta {H}{vap }^{\circ} for {H}{2} {O} is 44 {kJ} {mol}^{ 1}, then amount of heat required to evaporate 9 {~g} of {H}_{2} {O} is :