3.2.3
Chemical
Equilibrium
Section 3.2.3 covers dynamic equilibrium in a closed system, le Chatelier’s principle for temperature, pressure and concentration, why a catalyst leaves the position of equilibrium unchanged, the techniques used to investigate equilibria, the industrial compromise between equilibrium and rate, and the equilibrium constant Kc: expressions, calculations from equilibrium concentrations and estimating the position of equilibrium from its size.
Revision Notes
4 revision notes, in the order the specification teaches them.
Dynamic Equilibrium
Dynamic equilibrium: reversible reactions, equal forward and reverse rates, constant concentrations, closed systems and the position of equilibrium.
Start revising
Le Chatelier’s Principle
Le Chatelier’s principle: temperature, pressure and concentration changes, catalysts, and the ammonia and chromate equilibria as examples.
Start revising
Equilibria in Industry
Equilibria in industry: the Haber and Contact processes, compromise temperature and pressure, catalysts and evaluating yield data.
Start revising
The Equilibrium Constant Kc
Kc: expressions, units, calculations from equilibrium amounts, the magnitude of Kc and the effect of temperature.
Start revisingSummary Map
Download, print and revise the key facts of this topic at a glance.
Summary map
Download, print and revise the key facts of this topic at a glance.
Equilibrium Map
OCR A Level Chemistry A · 3.2.3 Chemical equilibrium
The whole section on one A4 page: dynamic equilibrium, Kc, concentration, pressure, temperature and catalysts, and industrial conditions, with worked examples.
© 2026 Online Learning System. For personal study: printing is allowed; editing, copying and redistribution are not.
Virtual Lessons
Recorded video lessons that teach the topic step by step.
The Virtual Lessons for 3.2.3 Chemical Equilibrium are being recorded.
MCQ Bank
Multiple-choice papers on this topic, marked the moment you submit.
The MCQ papers for 3.2.3 Chemical Equilibrium are being written.
SAQ Bank
Written, drawn and worked exam practice on this topic.
The exam practice papers for 3.2.3 Chemical Equilibrium are being written.
Revision Game
Match reagents to products, with your board's reagents and conditions.
The revision game for 3.2.3 Chemical Equilibrium is being built.
Study Cards
Pick a deck, then turn each card to check what you remember.
Specification
Every specification point in this topic, in the exam board's own words. Rate how confident you are with each one.
Self-assessment · 12 points
Sign in to rate how confident you feel about each point. Your ratings are saved to your account, follow you to any device, and appear beside your KASP analytics, kept apart from your marks.
3.2.3
- a
explanation that a dynamic equilibrium exists in a closed system when the rate of the forward reaction is equal to the rate of the reverse reaction and the concentrations of reactants and products do not change
Revise - b ii
application of le Chatelier's principle for homogeneous equilibria to deduce qualitatively the effect of a change in temperature on the position of equilibrium
Revise - b iii
application of le Chatelier's principle for homogeneous equilibria to deduce qualitatively the effect of a change in pressure on the position of equilibrium
Revise - b iv
application of le Chatelier's principle for homogeneous equilibria to deduce qualitatively the effect of a change in concentration on the position of equilibrium
Revise - c
explanation that a catalyst increases the rate of both forward and reverse reactions in an equilibrium by the same amount resulting in an unchanged position of equilibrium
Revise - d i
the techniques and procedures used to investigate changes to the position of equilibrium for changes in concentration
Revise - d ii
the techniques and procedures used to investigate changes to the position of equilibrium for changes in temperature
Revise - e
explanation of the importance to the chemical industry of a compromise between chemical equilibrium and reaction rate in deciding the operational conditions
Revise
Keep this note — free
Save your progress across every OCR topic. A free account remembers which topics you have covered, saves your question scores, and syncs across your phone and laptop.
- Track every topic you have finished
- Keep your practice-question scores
- No payment, no card, free forever
Already registered? Log in