### Residual Entropy

Posted:

**Sun Feb 17, 2019 11:08 pm**I know boltzman equation is S= k ln W, but when am I supposed to use S= R Ln W ( k times avogadro's number is R)?

Created by Dr. Laurence Lavelle

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

https://lavelle.chem.ucla.edu/forum/viewtopic.php?f=133&t=42373

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Posted: **Sun Feb 17, 2019 11:08 pm**

I know boltzman equation is S= k ln W, but when am I supposed to use S= R Ln W ( k times avogadro's number is R)?

Posted: **Sun Feb 17, 2019 11:12 pm**

I haven't come across problems incorporating what you mentioned. Since the value of W is yielded by (number of available positions)^(number of particles), then I think it's fair to assume that you will be using the value of k rather than R. W is in terms of individual particles and so is k, so I think you'll be safe just using k in problems that require the usage of this equation.

Posted: **Sun Feb 17, 2019 11:50 pm**

As I understand it, for the purposes of this course, S = k ln W should suffice. From the homework problems that I’ve seen, I haven’t used the second equation you mentioned.