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 Formation, \(\Delta H_{\rm f}^\circ \) 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 Solved Heat, q, is energy transferred between a system and Chegg.com