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I come from a civil engineering background and I'm about to start a masters in nuclear energy. I have no experience in thermodynamics and I've been doing a bit of revision before the course commences to get me up to speed but I'm really stuck on the following problem although it should be pretty simple.

Calculate the work done when 0.1kg of helium, confined in a cylinder by a piston, expands adiabatically from a volume of 0.1m

W=∫

In order to do the integration I need to know how pressure varies with volume so I tried using the following ideal gas equation

P=nRT/V

I get to this stage and I worked out that n=24.98 mol but then I become stuck. R is the ideal gas constant but how do I deal with the temperature?

The correct answer is 72kJ

Thanks

## Homework Statement

Calculate the work done when 0.1kg of helium, confined in a cylinder by a piston, expands adiabatically from a volume of 0.1m

^{3}and a pressure of 8 bar to a volume of 0.8m^{3}and a pressure of 0.4 bar.## Homework Equations

W=∫

^{V2}_{V1}P(V)dV## The Attempt at a Solution

In order to do the integration I need to know how pressure varies with volume so I tried using the following ideal gas equation

P=nRT/V

I get to this stage and I worked out that n=24.98 mol but then I become stuck. R is the ideal gas constant but how do I deal with the temperature?

The correct answer is 72kJ

Thanks

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