Standard enthalpy of vaporisation Delta_("vap") H^(@) for water at100^(@)C is40.66 kJ mol^(-1) . The internal energy change of vaporisation of water at100^(@)C ( in kJmol^(-1)) is:

Standard enthalpy of vaporisation Delta_("vap") H^(@) for water at100^

1.	Standard enthalpy of vaporisation Delta_("vap") H^(@) for water at100^(@)C is40.66 kJ mol^(-1) . The internal energy change of vaporisation of water at100^(@)C ( in kJmol^(-1)) is:
Answer» `+37.56` `-43.76` `+ 43.76` `+40.66` Solution :`underset(1 "mole")(H_(2)O(l)) rarrunderset("1 mole")(H_(2)O(g)), Deltan_(g)=1` `DeltaU =DeltaH - Deltan_(g)RT` `= 40.66xx 1000 J mol^(-1)-1 XX 8.314 JK^(-1) xx 373 K` `= 40660 - 3101 J mol^(-1)` `=37559 J mol^(-1)` `=37. 56 kJ mol^(-1)`