Delta Extrax Diamond Heights Disposable 3G D8 Gas The internal energy change (in J) when 90 g of water undergoes complete evaporation at `100^(@)C ` is ______ . (Given : `Delta H_("vap")` for water at 373 K = 41 kJ mol , `R = 8.314 JK^( 1) mol^( 1)`) Water Properties: Vaporization Heat vs. Temperature Charts and Calculator 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 Enthalpy of vaporization Wikipedia