Topic 26
Reaction Kinetics
Topic 26 covers rate equations, order, overall order, the rate constant, half-life, the rate-determining step and intermediates; deducing orders from concentration–time graphs, initial rates and the half-life method; interpreting graphs and calculating initial rates; the constant half-life of a first-order reaction and k = (0.693) / (t½); k from initial rates; mechanisms and the rate-determining step; the qualitative effect of temperature on k; and homogeneous and heterogeneous catalysis with the Haber, catalytic converter, oxides of nitrogen and Fe²⁺/Fe³⁺ examples.
Revision Notes
8 revision notes, in the order the specification teaches them.
Rate Equations, Orders and the Rate Constant
Rate equations: orders of reaction, the rate constant k, overall order and working out the units of k.
Start revising
Techniques for Measuring Rates
Measuring rates: titration, colorimetry, mass and gas-volume methods, continuous monitoring and the initial-rates method with clock reactions.
Start revising
Concentration–Time Graphs and Half-Life
Concentration–time graphs: deducing order from the shape, tangents and rates, half-life and first-order reactions, k from the half-life.
Start revising
Rate–Concentration Graphs and the Initial-Rates Method
The initial-rates method: rate–concentration graphs, deducing orders from tables of data, writing the rate equation and calculating k.
Start revising
The Iodine–Propanone Reaction
The iodine–propanone reaction: collecting rate data, the orders with respect to iodine, propanone and H⁺, and deducing the mechanism.
Start revising
Rate-Determining Step and Reaction Mechanisms
The rate-determining step: rate equations from mechanisms, mechanisms from rate equations, intermediates, and Sₙ1/Sₙ2 evidence from halogenoalkanes hydrolysis.
Start revising
Temperature, Activation Energy and the Rate Constant
Temperature and the rate constant: the Boltzmann distribution, the fraction of particles with E ≥ Eₐ, and why the rate and k rise with temperature.
Start revising
Heterogeneous and Homogeneous Catalysis
Catalysis: heterogeneous catalysts at surfaces (adsorption, desorption, the Haber process, catalytic converters) and homogeneous catalysts that are regenerated.
Start revisingSummary Map
Download, print and revise the key facts of this topic at a glance.
Summary maps
Download, print and revise the key facts of this topic at a glance.
Rate Equations Map
Cambridge International AS & A Level Chemistry (9701) · Topic 26 Reaction kinetics · Rate equations
The whole section on one A4 page: measuring a rate, rate equations, units of k, initial rates, graph shapes and half-life, with worked examples.
Mechanisms and Catalysts Map
Cambridge International AS & A Level Chemistry (9701) · Topic 26 Reaction kinetics · Mechanisms, temperature and catalysts
The whole section on one A4 page: the slow step, mechanisms from rate equations, temperature and k, how catalysts work, and homogeneous and heterogeneous catalysts.
© 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 Topic 26 Reaction Kinetics are being recorded.
MCQ Bank
Multiple-choice papers on this topic, marked the moment you submit.
The MCQ papers for Topic 26 Reaction Kinetics are being written.
SAQ Bank
Written, drawn and worked exam practice on this topic.
The exam practice papers for Topic 26 Reaction Kinetics are being written.
Revision Game
Match reagents to products, with your board's reagents and conditions.
The revision game for Topic 26 Reaction Kinetics 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.
Cambridge no longer issues a data booklet: the data you need are given in each question, and the syllabus has a Data section.
Self-assessment · 34 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.
26.1.1
26.1.2
26.1.3
- a
show understanding that the half-life of a first-order reaction is independent of concentration
Revise
26.1.4
26.1.5
- a
for a multi-step reaction: suggest a reaction mechanism that is consistent with the rate equation and the equation for the overall reaction
Revise - b
for a multi-step reaction: predict the order that would result from a given reaction mechanism and rate-determining step
Revise - c
for a multi-step reaction: deduce a rate equation using a given reaction mechanism and rate-determining step for a given reaction
Revise - d
for a multi-step reaction: identify an intermediate or catalyst from a given reaction mechanism
Revise - e
for a multi-step reaction: identify the rate determining step from a rate equation and a given reaction mechanism
Revise
26.1.6
- 26.1.6
describe qualitatively the effect of temperature change on the rate constant and hence the rate of a reaction
Revise
26.2.1
26.2.2
26.2.3
- 26.2.3
describe the mode of action of a homogeneous catalyst by being used in one step and reformed in a later step
Revise - a
describe the mode of action of a homogeneous catalyst, for example atmospheric oxides of nitrogen in the oxidation of atmospheric sulfur dioxide
Revise - b
describe the mode of action of a homogeneous catalyst, for example Fe2+ or Fe3+ in the I–/S2O82– reaction
Revise
Keep this note — free
Save your progress across every Cambridge 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