### Equations for 8.27

Posted:

**Sat Jan 23, 2016 8:40 pm**For this problem, it breaks up the two processes into irreversible and isothermic reactions. Which formulas am I supposed to use for each of them?

Created by Dr. Laurence Lavelle

https://lavelle.chem.ucla.edu/forum/

https://lavelle.chem.ucla.edu/forum/viewtopic.php?f=76&t=10451

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Posted: **Sat Jan 23, 2016 8:40 pm**

For this problem, it breaks up the two processes into irreversible and isothermic reactions. Which formulas am I supposed to use for each of them?

Posted: **Sat Jan 23, 2016 9:10 pm**

For part (a) it says there is an irreversible expansion against a constant external pressure. So you use w=-P_{external}V.

For part (b) it talks about an isothermal, reversible expansion.

You would use the work equation w=-nRTln(v_{f}/v_{i}). But in order to find how many moles there are, you would use the ideal Gas law PV=nRT and solve for n. Then from there you just plug and chug.

Hope this helps!

For part (b) it talks about an isothermal, reversible expansion.

You would use the work equation w=-nRTln(v

Hope this helps!