Expansion of a gas in vacuum is called free-expansion. Calculate the work done and the change in internal energy when 1 L of ideal gas expands isothermally into vacuum until its total volume is 5 L?
Work done, W = ${ -p }{ ext }$ (V2-V1)
As ${ p }{ ext }$ =0 , so W = -0(5-1) = 0
For isothermal expansion,
∆U = 0 as ∆T = 0