24 19. (a) Use Trouton's rule, Delta Hvap^circ approx (88 What is `Delta U` when `2.0` mole of liquid water vaporises at `100^(@)C`? The heat of vaporisation `(Delta H_("vap".))` of water at `100^(@)C` is `40.66 KJmol^( 1)`. 3. (a) Derive the integrated form of Clausius Clapeyron Entropy of vaporisation is given by the formula, \Delta S_{\text {vap. }}.. 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 Enthalpy Changes delta h Nuclear Power