TransWikia.com

Equilibrium Constants for Diatomic Gases at High Temperatures

Chemistry Asked on November 17, 2021

I’m new here and I haven’t taken chemistry beyond high school, so please forgive the ignorance. I am reading a book about hypersonic aerodynamics, and I am trying to connect some chemistry knowledge into my reading. I have four reactions listed in my book:

$$
begin{align}
ce{O2 &-> 2 O} &quad (pu{2000K} < T < pu{4000K})\
ce{N2 &-> 2 N} &quad (pu{4000K} < T < pu{9000K})\
ce{N &-> N+ + e-} &quad (T > pu{9000K})\
ce{O &-> O+ + e-} &quad (T > pu{9000K})
end{align}
$$

Now, the book doesn’t go into the chemistry here really at all. I know that some minor dissociation happens at cooler temperatures, and there will still be some diatomic oxygen/nitrogen at higher temperatures too. But I’m trying to answer for myself just how much is around at those temperatures, and how much they change in the ranges that they list. Assuming I remember correctly, I need the dissociation constants for this. However, I’m having trouble finding them.

NIST chemical reaction searching tool doesn’t seem to have the information I’m looking for, and Wolfram|Alpha (which generally helps) is not understanding what I’m trying to tell it… so I’m at a loss. My chemical engineer family member mentioned I could find it in the CRC Handbook of Chemistry and Physics, but unfortunately we can’t seem to find our copy. My chemistry-major friend in college knew that it was possible to get the numbers, but he couldn’t quite remember where I should start.

Either way, I’m looking for the equilibrium coefficients of:

$$
begin{array}{clr}
hline
# &text{Reaction} & T/pu{K} \
hline
1 & ce{O2 -> 2O} & 2000 \
2 & ce{O2 -> 2O} & 4000 \
3 & ce{N2 -> 2N} & 4000 \
4 & ce{N2 -> 2N} & 9000 \
5 & ce{N -> N+ + e-} & 9000 \
6 & ce{N -> N+ + e-} & 11000 \
7 & ce{O -> O+ + e-} & 9000 \
8 & ce{O -> O+ + e-} & 11000 \
hline
end{array}
$$

Can anyone either provide those values or help me find them somewhere? Even the reaction equilibrium constants that I can find are only listed at a single temperature (and never this high, because these temperatures are… uncommon).

Add your own answers!

Ask a Question

Get help from others!

© 2024 TransWikia.com. All rights reserved. Sites we Love: PCI Database, UKBizDB, Menu Kuliner, Sharing RPP