Solved Heat, q, is energy transferred between a system and Chegg.com Heating Curve The enthalpy of vapourisation of liquid water using the data : `H_(2)(g)+1 2O_(2)(g)rarr H_(2)O(l) Calculate the `K_b` for water given latent heat of vaporisation of water `540 Cal gm`. Standard enthalpy of vaporization (vapH) for water at 100C is 40.66 kJ.. Solved: For the reversible vaporization of water at $$100^0C$$ and 1 atmospheric pressure, $$Delta [Physics]