Thu August 09, 2012 By:

Sir, could you please explain how to solve this problem ? Two litres of an ideal gas at a pressure of 10 atm expands isothermally into vaccum until its total volume is 10 litres. How much heat is absorbed and how much work is done in the expansion? what would be heat absorbed and work done i.) if same expansion takes place against a constant external pressure of 1 atm? ii.) if the same expansion takes place to a final volume of 10 litres conducted reversibly?

Expert Reply
Tue August 14, 2012

We have q = – w = pex (10 – 2) = 0(8) = 0

No work is done; no heat is absorbed.

We have q = – w = pex (8) = 8 litre-atm

We have q=-w=2.303X10log (10/2)=16.1latm

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