### Entropy

Posted:

**Thu Feb 08, 2018 11:38 pm**What is the difference between S°m, S°r, and S°f?

Created by Dr. Laurence Lavelle

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

https://lavelle.chem.ucla.edu/forum/viewtopic.php?f=135&t=27183

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Posted: **Thu Feb 08, 2018 11:38 pm**

What is the difference between S°m, S°r, and S°f?

Posted: **Fri Feb 09, 2018 12:08 am**

I'm not exactly sure because you didn't give context, but S^0 m is most likely entropy for the melting point, r is for reactants and f is for final.

Posted: **Fri Feb 09, 2018 1:39 am**

S^o (m) is the standard molar entropy (the values in the back of the textbook). I think S^o (f) is similar to the S^o (m). I don't quite know what S^o (r) is though.

Posted: **Fri Feb 09, 2018 10:12 am**

S^o r is the standard reaction entropy

Posted: **Fri Feb 09, 2018 5:46 pm**

This is what I think:

S°m would be the Standard Molar Entropy

S°r would be the Standard Reaction Entropy

S°f would be the Standard Entropy of Formation

S°m would be the Standard Molar Entropy

S°r would be the Standard Reaction Entropy

S°f would be the Standard Entropy of Formation

Posted: **Fri Feb 09, 2018 8:37 pm**

is there an entropy of fusion?

Posted: **Sat Feb 10, 2018 8:18 am**

Dylan Mai 1D wrote:is there an entropy of fusion?

I don't think it is a tabulated value in any of the tables or appendixes in the textbook, but you can definitely calculate it similarly to calculating the entropy of vaporization.

entropy of fusion = enthalpy of fusion/melting point (Tb)

Posted: **Sat Feb 10, 2018 9:55 am**

S°m is molar entropy.

S°f is standard entropy of formation.

S°r is standard reaction entropy.

S°f is standard entropy of formation.

S°r is standard reaction entropy.