(adsbygoogle = window.adsbygoogle || []).push({}); 1. The problem statement, all variables and given/known data

i.) An ideal gas occupies a volume of 2.5 dm3 at a pressure of 0.3 MPa. If the gas is compressed isothermally by a constant external pressure, Pext, so that the final volume is 0.5 dm3, what is the smallest value that the external pressure can have? [2 marks]

ii.)How much work has been done on the gas? [4 marks]

iii.) What is the internal energy change in the gas? [1 mark]

iv.)How much thermal energy has been absorbed by the gas? [2 marks]

v.) What is meant by a reversible process involving an ideal gas? Would the work done on the gas in the above problem be greater if the process had been carried out reversibly? [2 marks]

For part i I just used the equation p1v1=p2v2 and came up with the answer 1.5MPa.

For part ii I used the equation p(Vf-Vi) and got the answer W = -0.3 MJ but i'm not sure if I used the right equation, I originally used the equation W = int pdV but my answer came out as 0. I'm just not sure on the whole on this question, really.

As the process was isothermal, am I right in thinking there was no change in the internal energy of the gas. And because of this the answer for part iv is just 0.3MJ?

Not too sure about part v either. I really need to work on this area...

If anyone could point me in the right direction i'd be thrilled, cheers.

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# Homework Help: Simple Thermodynamics

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