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Question
Expansion of a gas in vacuum is called free expansion. Calculate the work done and the change in internal energy when 1 litre of ideal gas expands isothermally into vacuum until its total volume is 5 litre?
Solution
During free expansion, external pressure is zero, so Work done, w = – pextΔV
= – 0(5 – 1) = 0
Since the gas is expanding isothermally, therefore, q = 0
ΔU = q + w = 0 + 0 = 0
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