### S = q/T

Posted:

**Tue Feb 11, 2020 4:59 pm**When using S = q/T, does the temperature need to be constant? Thanks in advance!

Created by Dr. Laurence Lavelle

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

https://lavelle.chem.ucla.edu/forum/viewtopic.php?f=133&t=59146

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Posted: **Tue Feb 11, 2020 4:59 pm**

When using S = q/T, does the temperature need to be constant? Thanks in advance!

Posted: **Tue Feb 11, 2020 5:02 pm**

Yep! If you have changing temperature then you use delta S = n C ln (T2/T1)

Posted: **Tue Feb 11, 2020 5:51 pm**

yes, the temperature is constant for that equation. if the temperature were to change you would use S = C x ln (T2/T1). for C you would use either Cv or Cp depending on which is constant.

Posted: **Tue Feb 11, 2020 11:03 pm**

Yes, that equation assumes that temperature is constant.

Posted: **Tue Feb 11, 2020 11:05 pm**

What is this equation used for?

Posted: **Wed Feb 12, 2020 11:04 am**

This equation is used to find entropy when the temperature is constant. If the temp or volume change, you use the equations delta S= nRln(V2/V1) or delta S= nCln(T2/T1).