CHAPTER 8 If Delta H_(vaporisation) of substance X (l) (molar mass : 30 g mol) is 300 J g at it\'s boling Standard enthalpy of vapourisation \Delta _ { \mathrm { vap } } \mathrm {.. 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 PPT For all phase changes the sign of S and H is always going to be the same PowerPoint Presentation ID:5755390 3 Ways to Calculate Vapor Pressure wikiHow