## Boltzman's Entropy Equation

Boltzmann Equation for Entropy: $S = k_{B} \ln W$

Andrew F 2L
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Joined: Sat Aug 17, 2019 12:17 am

### Boltzman's Entropy Equation

I need help understanding the idea of microstates and why we use them in Boltzmann's equation for entropy. Is it referring to like rotational and the kinetic energy of molecules that they can occupy? Thank you!

Sukanya Mohapatra 2G
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Joined: Sat Aug 17, 2019 12:18 am
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### Re: Boltzman's Entropy Equation

Microstates is a term used to describe the number of different possible arrangements of molecular position and kinetic energy at a particular thermodynamic state. A process that gives an increase in the number of microstates increases the entropy.

Ashley Wang 4G
Posts: 103
Joined: Wed Sep 11, 2019 12:16 am

### Re: Boltzman's Entropy Equation

Because Boltzmann's equation calculates the residual entropy, which is the entropy of the sample at 0 Kelvin, we are assuming the entropy arises only from positional disorder in the sample (i.e. linked to the number of microstates) that survives at that temperature, we disregard the entropy resulting from thermal energy and motion. I would say this is also disregarding the rotational and kinetic energy, since motion theoretically ceases at 0 Kelvin. The entropy thus results solely from the possible positional arrangements.

Caroline Zepecki
Posts: 101
Joined: Fri Aug 09, 2019 12:16 am

### Re: Boltzman's Entropy Equation

Microstates refers to the possible arrangements, so for example, when calculating W, it would be micro states ^ # of atoms

Mai V 4L
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Joined: Fri Sep 28, 2018 12:23 am

### Re: Boltzman's Entropy Equation

Can someone please share their favorite youtube videos or graphics to help remember this? Thanks.

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