Chemical equilibrium – N₂O₄ ⇌ 2NO₂ shift

ChemistryKinetics & EquilibriumAges 16–17

A sealed flask holds the equilibrium N₂O₄ (colorless) ⇌ 2NO₂ (reddish-brown). Change the temperature or compress/expand the flask, then watch the flask's color and the concentration-vs-time graph: the system shifts exactly as Le Chatelier's principle predicts and settles into a new equilibrium, while K itself only changes with temperature.