Finding Delta H using ln P vs 1 T (Hvap Lab) 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 = Solved: H v a p for water is 40.7 KJ mol 1 . The entropy of vapo [Chemistry] PPT For all phase changes the sign of S and H is always going to be the same PowerPoint Presentation ID:5755390 Delta S` for vapouization of 900g water (in KJ K ) is `Delta H_(Vap)=40KJ(mol)^ 1 `