Finding Delta H using ln P vs 1 T (Hvap Lab) Standard enthalpy of vapourisation `Delta_("vap")H^( )` for water at `100^@C` is `40.66 kJ mol^( 1)`. The internal energy of vapourisation of water at `100^@C` (in kJ `mol^( 1)`) is (Assume water vapour to behave like thermodynamics $\Delta \bar{h}_{vap}$ and $\Delta \bar{s}_{vap}$ from vapor pressure vs. temperature data Chemistry Stack Exchange 5 gram Delta 8 Disposable THC HHC Vape Pen with Preheat 4asvapes Vaping Products 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 Standard Enthalpy of Formation, \(\Delta H_{\rm f}^\circ \)