## Irreversible Expansion

$\Delta S = \frac{q_{rev}}{T}$

Hannah Lee 2F
Posts: 117
Joined: Thu Jul 11, 2019 12:15 am

### Irreversible Expansion

How would you calculate the entropy of an irreversible expansion of an ideal gas at constant temperature? Could that occur at changing temperatures?

005324438
Posts: 51
Joined: Sat Aug 24, 2019 12:16 am

### Re: Irreversible Expansion

If the temperature is constant, we have to use the equation S=nKln(V2/V1), reversible or irreversible. A reversible change can happen without a constant temperature, but if the pressure is constant, we have to use different equations depending on what is constant.

Caroline Zepecki
Posts: 101
Joined: Fri Aug 09, 2019 12:16 am

### Re: Irreversible Expansion

If the temperature is constant, but you have changing pressure instead, you would use S = nKln(p1/p2), so same equation but replace V2 with P1 and vice versa because they're inversely proportional.

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