Expansion of a gas in vaccum is called free expansion.Calculate the work done and the change in internal energy when 1 litre of ideal gas expands isothermally into vaccum until its total volume is 5 litre?

Explanation

`w= -P _("ext") DeltaV`. As `P_(ext) = 0` , therefore, `w=0` . ltbrlt As internal energy of an idealgas depends only on temperature, therefore,for isothermal expansion of an ideal gas , internalenergy remains constant, i.e., `DeltaU =0`. [ Also,remember that as`H= U +PV, DeltaH = Delta ( U+PV)= DeltaU +P DeltaV = DeltaU _nR ( DeltaT)`. For isothermal process, `DeltaT = 0`, and also `DeltaU =0` as stated above, therefore, `DeltaH =0 ]`