🔄 Comparing Static and Dynamic Equilibrium

Understanding the distinction between static and dynamic equilibrium is essential for exam success. Here is a direct comparison using the syllabus language.

🧪 Chemical Example: N₂O₄ ⇌ 2NO₂

Dinitrogen tetroxide (N₂O₄, colourless) decomposes into nitrogen dioxide (NO₂, brown gas) in a reversible reaction. In a sealed flask at constant temperature, the system reaches dynamic equilibrium: N₂O₄ is constantly breaking apart into NO₂ (forward) and NO₂ is constantly recombining into N₂O₄ (reverse). At equilibrium, the colour of the gas mixture stays constant — a steady brown — because the rates are equal. If you opened the flask, NO₂ gas would escape, the reverse reaction would slow, and equilibrium would be destroyed. This is why a closed system is essential.