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I'm trying to measure the $K_c$ of the equilibrium reaction

$$\ce{2 NO2 (g) <=> N2O4 (g)}$$

in different temperatures. How would I do this do this in a normal school laboratory? I was thinking of shining (laser) light through a test tube that contained $\ce{NO2 (g)}$ and looking at the intensity of light emitted. $\ce{NO2 (g)}$ is dark-reddish brown and $\ce{N2O4 (g)}$ is colorless. That means that the more to the right the equation is, the more light will be emitted.

However, I don't think this would give me accurate values for $K_c$. Are there any other methods that I could use to do this which preferably don't require advanced equipment (which I don't have)?

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  • $\begingroup$ Nice question! You've got me thinking. So you know, I took the LaTeX out of the title because it makes things look messy in searches. $\endgroup$ – hBy2Py May 12 '16 at 13:14
  • $\begingroup$ @Brian Oh, thanks! I didn't realize that, but it makes sense. I'll keep that in mind for the future! Also, thanks for correcting the equation and tags – that was a silly mistake on my part :) $\endgroup$ – Skeleton Bow May 12 '16 at 13:25
  • $\begingroup$ No prob - welcome to the site! $\endgroup$ – hBy2Py May 12 '16 at 13:31
  • $\begingroup$ If you have an equipment, that allows you to measure pressure change during reaction, you can easily compute partial pressures and equilibrium constant. $\endgroup$ – Vadim Shkaberda May 16 '16 at 6:33
  • $\begingroup$ @VadimShkaberda wow, that's a great idea! I can measure pressure, and I probably could use these calculate that and try to find $K_c$ that way. I'll look into that! $\endgroup$ – Skeleton Bow May 16 '16 at 17:59