### chen discussion

Posted:

**Tue Feb 04, 2020 4:26 pm**for #1, we used the equation delta s= nRln(V2/V1). what is n equal to in the problem? is it equal to 1 because we are calculating molar entropy?

Created by Dr. Laurence Lavelle

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

https://lavelle.chem.ucla.edu/forum/viewtopic.php?f=133&t=58287

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Posted: **Tue Feb 04, 2020 4:26 pm**

for #1, we used the equation delta s= nRln(V2/V1). what is n equal to in the problem? is it equal to 1 because we are calculating molar entropy?

Posted: **Tue Feb 04, 2020 6:05 pm**

Do you mind posting the entire question?

Posted: **Wed Feb 05, 2020 12:20 pm**

the question is "calculate the change in molar entropy of carbon dioxide that is allowed to expand isothermally to 10 times its initial volume (treat carbon dioxide as an ideal gas, Cv,m=3/2R)"

Posted: **Thu Feb 06, 2020 11:11 am**

Yes, molar entropy means entropy for 1 mole of substance. So number of mole equals to one in this question.

Posted: **Thu Feb 06, 2020 9:03 pm**

When do we use C and when do we use R?

Posted: **Thu Feb 06, 2020 9:05 pm**

Diana_Diep2I wrote:When do we use C and when do we use R?

C = 3/2R at constant volume and C = 5/2R at constant pressure.