The enthalpy of vaporization of \mathrm{H}{2} \mathrm{O}(1) is x \mathrm{~kJ} \mathrm{mol} and enthalpy of formation of water vapour \mathrm{ykJ} \mathrm{mol}. Enthalpy of formation of when do we use this two equation? is there a specific condition on when to use them ? : r ChemicalEngineering phase diagram water.svg Standard enthalpy of vaporisation \Delta _ { v a p } H ^ { \circ } for a .. Enthalpy of vaporization Wikipedia Hybrid Delta 8 Pen