# Do gasses ever truly reach a state of internal thermodynamic equilibrium?

**URL:** https://boards.straightdope.com/t/do-gasses-ever-truly-reach-a-state-of-internal-thermodynamic-equilibrium/914964
**Category:** Factual Questions
**Created:** [July 10, 2020, 7:13pm UTC](https://boards.straightdope.com/t/do-gasses-ever-truly-reach-a-state-of-internal-thermodynamic-equilibrium/914964 "2020-07-10T19:13:34Z")
**Posts on this page:** 2
**Page:** 2

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### Author: ![am77494](https://avatars.discourse-cdn.com/v4/letter/a/d2c977/32.png) [@am77494](https://boards.straightdope.com/u/am77494)
#### Post date: [July 14, 2020, 12:29am UTC](https://boards.straightdope.com/t/do-gasses-ever-truly-reach-a-state-of-internal-thermodynamic-equilibrium/914964/21 "2020-07-14T00:29:31Z")

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> [@Max\_S](#):
>
> I believe you are mistaken

Maybe, but please check out the links. This is also why I tried to get our definitions consistent.

> [@Max\_S](#):
>
> Temperature is said to be intensive at equilibrium, but specific internal energy is extensive and proportional to size

Wikipedia includes “Specific Internal Energy” as an example of an intensive property. I am including a screenshot but you can check for yourself at (cite) : [Intensive and extensive properties - Wikipedia](https://en.m.wikipedia.org/wiki/Intensive_and_extensive_properties)

Screenshot of cite with red underline of relevant part :  
[![Imgur](https://i.imgur.com/FbRyL1n.jpeg "imgur.com") ](https://imgur.com/FbRyL1n)

> [@Max\_S](#):
>
> It is also measured in joules, not joules per kg which is effectively a measure of acceleration.

Specific Internal Energy **is measured** in J/kg or J/mol as mentioned above in my post. I have a feeling that you are not reading the cites, so I am citing and attaching a screenshot with red underline : [Internal energy - Wikipedia](https://en.m.wikipedia.org/wiki/Internal_energy)

[![Imgur](https://i.imgur.com/Q7sdrcc.jpeg "imgur.com") ](https://imgur.com/Q7sdrcc)

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### Author: ![Max\_S](https://avatars.discourse-cdn.com/v4/letter/m/46a35a/32.png) [@Max\_S](https://boards.straightdope.com/u/Max_S)
#### Post date: [July 14, 2020, 12:56am UTC](https://boards.straightdope.com/t/do-gasses-ever-truly-reach-a-state-of-internal-thermodynamic-equilibrium/914964/22 "2020-07-14T00:56:05Z")

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Ack, I had confused specific internal energy with internal energy.

> [@am77494](#):
>
> This is where you confused me because this is not Classical Thermodynamics. A gas in Classical Thermodynamics is a continuum and not discrete particles in motion. In my opinion, you are mixing Classical TD and Statistical Mechanics in the question but want the answer purely from the Classical TD

I suppose I have in mind a combination of pre-Boltzmann classical thermodynamics and kinetic theory. It should all date to around the 1870s, and in my experience, this was all that was taught in public school.

~Max

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