# Density computation for high temperature, low pressure argon

1. Feb 17, 2016

### pyroknife

I am trying to compute the density of argon given the following conditions:
T = 7000 K
P = 21331 Pa

For typical gases, I do not believe the ideal gas law would hold for such a high temp&low pressure regime, but since Argon is largely non-reactive, do you guys think using the ideal gas law would be appropriate here to compute the density?

2. Feb 17, 2016

### BvU

So far above http://www.nist.gov/data/PDFfiles/jpcrd363.pdf [Broken] and so far below pc the ideal gas law is perfect.

Last edited by a moderator: May 7, 2017
3. Feb 17, 2016

### pyroknife

Hmm thank you for the post. Is this largely become Ar is an atom?

For example, I cannot use the ideal gas law if it was instead nitrogen gas (N2) since it will dissociate before this temperature, but I believe the temperature is above $T_c$ and the pressure is below $P_c$.

Last edited by a moderator: May 7, 2017
4. Feb 17, 2016

### BvU

You can use the ideal gas law for N under those (dissociated) conditions.

5. Feb 17, 2016

### pyroknife

But not for $N_2$ correct?

6. Feb 17, 2016

### BvU

If there is no http://www.nist.gov/data/PDFfiles/jpcrd39.pdf [Broken]http://www.nist.gov/data/PDFfiles/jpcrd39.pdf [Broken] then you can't use the ideal gas law, correct !

Last edited by a moderator: May 7, 2017