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)`)

90 g of water spilled out from a vessel in the room on the floor. Assuming that water vapour behaving as an ideal gas, calculate the internal energy change when the spilled water undergoes complete evaporation at 100^(@)C . (Given the molar enthalpy of vaporisation of water at 1 bar and 373 K = 41 kJ mol^(-1) ).

Assuming that water vapour is an ideal gas, the internal energy change (Delta U) when 1 mol of water is vapourised at 1 bar pressure and 100^(@)C , (Given: Molar enthalpy of vapourization of water at 1 bar and 373K=41 kJ mol^(-1) and R=8.3J mol^(-1)K^(-1) ) will be:

The value for DeltaU for the reversible isothermal evaporation of 90 g water at 100^(@)C will be (DeltaH_("evap")" of water "=40.8" kJ mol"^(-1), R=8.314"J K"^(-1)"mol"^(-1))

18g of water is takento prepare the tea. Find out the internal energy of vaporisation at 100^(@) C. (Delta_(vap)H for water at 373 K 373 K is 40.66kJ mol^(-1))