Hvap for water is 40.7 KJ `mol^(1)` . The entropy of vaporization of water is: 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 : Latent Heat of Vaporization Delta Hvap of Water calculated by corresponding states correlation in a one cell excel formula Chem Eng Musings Properties of Liquids Using Heat of Fusion or Vaporization to Find the Heat Needed to Melt or Boil a Substance Chemistry Study.com