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

A sample of 1.00 mol of an ideal diatomic gas, initially at pressure P and volume V, expands until it has a pressure of 2P and a volume of 2V. What's the entropy change in the gas on this process?

2. Relevant equations

2nd Maxwell relation:

4th Maxwell relation:

PV = nRT

3. The attempt at a solution

[tex]\frac{\partial S}{\partial V}= \frac{nR}{V}[/tex]

[tex]\frac{\partial S}{\partial P} = -\frac{nR}{P}[/tex]

I found out S by doing the standard procedure: integrating the first one and deriving in relation to P to find the function in relation to P. The expression for S i found was:

[tex]S=nR(lnV-lnP)[/tex]

But the variation of S is always 0 this way, and that's not the solution...

**Physics Forums | Science Articles, Homework Help, Discussion**

Dismiss Notice

Join Physics Forums Today!

The friendliest, high quality science and math community on the planet! Everyone who loves science is here!

The friendliest, high quality science and math community on the planet! Everyone who loves science is here!

# Calculation of variation of entropy knowing state's equation

**Physics Forums | Science Articles, Homework Help, Discussion**