Internal energy and enthalpy Physical Chemistry I Class Fiveable Standard enthalpy of vapourisation `Delta_("vap")H^( )` for water at `100^@C` is `40.66 kJ mol^( 1)`. The internal energy of vapourisation of water at `100^@C` (in kJ `mol^( 1)`) is (Assume water vapour to behave like How Does a Delta 8 Disposable Vape Work? Hamilton Devices Solved Heat, q, is energy transferred between a system and Chegg.com vp vs temp.svg