Topic 9B Equilibria
Use this landing page to move between the three Equilibria revision pages of Topic 9. Each card links to a focused page with inline checks, worked examples and exam-style FAQs.
Choose a Equilibria Page
Equilibria are reversible reactions that settle into a state of balance. These pages define dynamic equilibrium, use Le Chatelier’s principle to predict how the position of equilibrium responds to changes, and apply both to the compromises made in the Haber and Contact processes.
Key idea: A system at equilibrium is dynamic: both reactions keep going at the same rate, so the concentrations stay constant, and a change in conditions moves the position of equilibrium to reduce the effect of that change.
Dynamic Equilibrium
Dynamic equilibrium: reversible reactions, equal forward and reverse rates, constant concentrations, closed systems and the position of equilibrium.
Start revisingLe Chatelier’s Principle
Le Chatelier’s principle: temperature, pressure and concentration changes, catalysts, and the ammonia and chromate equilibria as examples.
Start revisingEquilibria in Industry
Equilibria in industry: the Haber and Contact processes, compromise temperature and pressure, catalysts and evaluating yield data.
Start revisingHow to Use These Pages
Learn the two features of dynamic equilibrium first, then practise Le Chatelier on the ammonia equilibrium until every direction is automatic, and use the industry page to see how yield and rate are traded off.
Exam focus: For every shift give the direction and the reason: “moves to the right, the side with fewer gas molecules, to reduce the pressure”. Say “position of equilibrium”, and remember a catalyst never moves it.
Copyright notice: This revision page, including its written explanations, layout and teaching sequence, is produced for Online Learning System by Dr. Mohammed Al-Fatah. It is intended for student revision and may not be copied, redistributed or republished without permission.
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