### Explaining Boltzmann's Equation

Posted:

**Tue Feb 12, 2019 12:01 am**What is the explanation behind Boltzmann's Equation? What exactly does it solve for?

Created by Dr. Laurence Lavelle

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

https://lavelle.chem.ucla.edu/forum/viewtopic.php?f=132&t=42002

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Posted: **Tue Feb 12, 2019 12:01 am**

What is the explanation behind Boltzmann's Equation? What exactly does it solve for?

Posted: **Tue Feb 12, 2019 12:40 am**

Boltzmann's equation calculates positional/residual entropy using statistics.

Its form is S=kBlnW.

W is equal to the number of microstates (how many positions an element can be in in a molecule) raised to the power of the number of molecules in the system.

kB is a constnant.

Its form is S=kBlnW.

W is equal to the number of microstates (how many positions an element can be in in a molecule) raised to the power of the number of molecules in the system.

kB is a constnant.

Posted: **Thu Feb 14, 2019 10:00 am**

The actual derivation for Boltzmann's equation is quite complicated and involves a lot of multivariable calc, so I would just take it for granted.

Posted: **Sat Feb 16, 2019 5:01 pm**

We use Boltzmann's equation to calculate residual or statistical entropy within a system. This differs from the majority of calculations that we do, finding the CHANGE in entropy.

Posted: **Sat Feb 16, 2019 7:54 pm**

I found a relatively accessible derivation of the formula here: http://www.eoht.info/page/S+%3D+k+ln+W

Posted: **Sat Feb 16, 2019 9:42 pm**

Boltzmann's equation solves for statistical or residual entropy, and is based on the number of microstates and number of molecules in a system.

Posted: **Tue Feb 19, 2019 9:42 pm**

how do you know how many molecules are present?