question_answer 2)

Two litres of an ideal gas at a pressure of 10 atm expands isothermally into a vacuum until its total volume is 10 litres. How much heat is absorbed and how much work is done in the expansion?

Answer:

Work in free expansion or work done against zero pressure in vacuum is also zero. \[{{w}_{\exp }}=-{{P}_{ext}}\times 8=-0\times 8=0\] \[\therefore \]\[q=-w=0\] \[\therefore \] Heat change and work done, both are zero.