THCh Guide: Everything You Need to Know Eighty Six Heat of Vaporization: Clausius Clapeyron For the vaporisation of water : `H_(2)O (I) hArr H_(2)O(g)` [1 atm. Pressure] Given : `Delta S = 120 JK^( 1)` and `Delta H =+45.0 kJ`. Evaluate the temperature at which liquid water THE ENTHALPY OF A SYSTEM Enthalpy (H) is the total heat content of a system, defined as its internal energy (E) plus the product of its pressure (P) and volume (V) (H = For the vaporisation of water : `H_(2)O (I) hArr H_(2)O(g)` [1 atm. Pressure] Given : `Delta S = 120 JK^( 1)` and `Delta H =+45.0 kJ`. Evaluate the temperature at which liquid water If Delta H_(vaporisation) of substance X (l) (molar mass : 30 g mol) is 300 J g at it\'s boling