Standard enthalpy of vaporization (vapH) for water at 100C is 40.66 kJ.. Solved Heat, q, is energy transferred between a system and Chegg.com Predicting the Enthalpy of Vaporization and Calculating the Entropy of Vaporization of 87 Octane Gasoline Using Vapor Pressure 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`. Calculating Energy Change Phase Change Easy Peasy All in One High School