Constant, Not Equal

You'll learnwhy a reaction that looks finished is still running hard in both directions.

A sealed flask of colourless gas turns brown, then stops turning brown, and the whole reaction looks finished. It is not — underneath the still surface, molecules are converting both ways at exactly matched speed, which is why nothing moves. Twelve short steps; press Next for each one.

12 STEPS · 6 QUICK CHECKS · N₂O₄(g) ⇌ 2 NO₂(g) · rate_f = rate_r · v4

a flask that goes quiet while both directions run flat out

Before you start

What you're looking at

A sealed flask of colourless N2O4 gas, darkening as it turns into brown NO2.

The question

The colour stops changing. Did the reaction stop, or is something still going on underneath?

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