## Positional entropy

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

Abigail Menchaca_1H
Posts: 104
Joined: Sat Sep 07, 2019 12:19 am

### Positional entropy

What does positional entropy mean and what’s the difference from thermal entropy?

Sukanya Mohapatra 2G
Posts: 100
Joined: Sat Aug 17, 2019 12:18 am
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### Re: Positional entropy

Positional entropy refers to the number of molecular positions or arrangements that a system can have, while thermal entropy refers to the amount of thermal energy that is not available for any useful work.

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

### Re: Positional entropy

Positional entropy is the entropy of a substance at 0 Kelvin, arising from the substance's positional only (i.e. eliminating thermal entropy). This boils down to the number of possible microstates, which is linked to the positional entropy by Boltzmann's Equation.

Thermal entropy takes into account the increase in "disorder" of the substance when it's heated to a certain temperature, from vibrational energy, etc.

Mai V 4L
Posts: 111
Joined: Fri Sep 28, 2018 12:23 am

### Re: Positional entropy

Sukanya Mohapatra 2G wrote:Positional entropy refers to the number of molecular positions or arrangements that a system can have, while thermal entropy refers to the amount of thermal energy that is not available for any useful work.

Why is it not available? because it becomes disoredered? or exhaust?

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