A piston-cylinder device initially contains 0.3 kg of nitrogen gas at 160 kPa and 140oC. The nitrogen is now expanded isothermally to a pressure of 100 kPa. Determine the boundary work done during this process.


  1. Answer:

    Work done by the gas is given as

    W = 1.72 \times 10^4 J


    As we know that the process is isothermal so here work done is given as

    W = nRTln(\frac{P_1}{P_2})

    here we know that

    n = \frac{w}{M}

    n = \frac{300}{28} = 10.7 moles

    now we have

    W = 10.7 (8.31)(273 + 140) ln(\frac{160}{100})

    so we have

    W = 1.72 \times 10^4 J

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