Chemistry revision

How to revise A-level Chemistry

Find the gaps, practise chemical reasoning and use each mistake to choose the next task.

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Lead authorRobin GibbonsFounder & CEO·Latimer Tuition
Reviewed byHeather LatimerTutor Matching & Customer Service·Latimer Tuition

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Recall the chemistry, then use it

To revise A-level Chemistry, test a small part of the course from memory, use it in an exam question, mark your reasoning and retry the specific step you got wrong. Repeat this across physical, organic and inorganic chemistry, returning to earlier topics after a gap. Reading notes helps repair a gap; answering with the notes closed shows whether the repair worked.

Start with your own specification and a recent marked question. Choose one weakness you can name, such as converting concentration units or explaining a trend, rather than deciding to “revise all of chemistry”.

This guide is for students taking A-level Chemistry in England. The subject examples fit common A-level skills, but topic coverage, paper combinations, data sheets and accepted conventions depend on your board and specification. AS and International A levels have different requirements.

The detailed chemistry examples below draw on AQA 7405. Match them to the content and conventions of your own course before using them for assessment practice.

Find the gaps before choosing resources

Use your specification as a checklist of what you need to do, rather than a list of pages to reread. Our guide to revising from an exam specification explains how to set this up.

Confirm the qualification
Find the board, specification code and exam-year version from your teacher or course documents. Collect the matching specification, data booklet, question papers, mark schemes and examiner reports. Keep a few unseen papers for later timed practice.
Sample all three areas
Choose a short physical calculation, an organic reaction or mechanism, and an inorganic explanation from topics already taught. Attempt them without notes. Record whether you could recall the facts, choose the method and complete the reasoning.
Label the problem accurately
Separate missing knowledge from a misunderstanding, a mathematical slip or a missed instruction. If you knew n = cV but used the wrong volume units, another page of mole definitions is unlikely to fix the actual error.
Choose the next task from the evidence
For missing knowledge, retrieve a small set of facts and check them. For a concept gap, study one explanation and explain it back. For application, tackle a fresh question whose context differs. Ask your teacher about a step you still cannot explain.

Change the practice to suit the chemistry

Keep recall prompts small enough to answer from memory, then add a task that makes you use the answer. The examples below are choices for revision, not a complete syllabus.

Area	Retrieve	Apply and check
Physical chemistry	Equations, symbol meanings, units and the conditions under which a relationship applies.	Choose an equation without a topic label; show substitutions, units and mole ratios. Explain what a changed condition would do before calculating.
Organic chemistry	Functional groups, reagents, conditions, products and required mechanisms.	Rebuild a reaction map from a blank page. For each arrow, add the reagent and conditions; practise drawing electron movement and explaining why that product forms.
Inorganic chemistry	Required observations, equations, oxidation states and periodic trends.	Separate an observation from its explanation. Predict an unfamiliar comparison using charge, structure or electron arrangement, then check the relevant specification detail.

Calculation practice

Worked calculation: make the units do some of the checking

Constructed practice question: 25.0 cm³ of sodium hydroxide solution is exactly neutralised by 20.0 cm³ of hydrochloric acid of concentration 0.100 mol dm⁻³. Find the sodium hydroxide concentration.

Write the balanced equation: HCl + NaOH → NaCl + H₂O. The acid and alkali react in a 1:1 mole ratio.
Convert the acid volume: 20.0 cm³ ÷ 1000 = 0.0200 dm³. The concentration is per dm³, so the volume must be in dm³ when using n = cV.
Calculate acid moles: n(HCl) = 0.100 mol dm⁻³ × 0.0200 dm³ = 0.00200 mol.
Use the ratio: n(NaOH) = 0.00200 mol. Equal reacting moles here do not mean equal concentrations: the solution volumes differ.
Find the alkali concentration: c(NaOH) = 0.00200 mol ÷ 0.0250 dm³ = 0.0800 mol dm⁻³ (three significant figures).

Repair a specific error: suppose you wrote 0.100 × 20.0 = 2.00 mol. Add the units to that line: the volume is in cm³ while the concentration uses dm³. Convert the volume, redo the line and explain the factor of 1000. Do not just copy the final answer. If you forget both conversions, the errors can even cancel in the final concentration while leaving an incorrect mole value in your working.

For a fresh check, use 10.0 cm³ of the same acid to neutralise 25.0 cm³ of alkali. Explain why the answer is half the previous concentration, then calculate it: 0.0400 mol dm⁻³. In a different reaction, establish the balanced-equation ratio again; 1:1 is not a universal titration rule.

Organic practice

Draw mechanisms as electron movement

Use mechanisms to explain bond changes. A curly arrow represents the movement of an electron pair, so its tail must start at a bond or lone pair that supplies those electrons.

Constructed nucleophilic substitution drill: draw bromoethane reacting with hydroxide to form ethanol and bromide. Show the C–Br bond as polar, with the carbon partially positive. Draw one curly arrow from a lone pair on the hydroxide oxygen to that carbon, and another from the C–Br bond to Br. The C–O bond forms and the C–Br bonding pair goes to bromine.

A weak drawing starts the first arrow at the partially positive carbon and points towards hydroxide. Correct it by asking, “Where are the electrons coming from?” The hydroxide lone pair supplies them, so reverse that arrow and check the second arrow separately. Check charges as well: hydroxide has a negative charge before the reaction and bromide has one afterwards.

Next, redraw the mechanism from a blank starting structure. Then change the haloalkane within the examples your course requires. Keep reagents and conditions alongside the reaction: aqueous hydroxide is used for the substitution example; conditions matter when distinguishing substitution from competing reactions. Use your board’s mechanism conventions and required reaction list rather than memorising an unlabelled online diagram.

Inorganic practice

Make inorganic explanations causal

Test whether you can explain a trend as well as state it. AQA 7405 includes Period 3 trends explained through structure and bonding. For a melting-point comparison, first identify the structure and the particles involved, then the bonding or attractions relevant to melting. Connect those details to the energy needed. “The bonds are stronger” is incomplete if you have not identified what is being overcome.

Try this revision task with two Period 3 substances from your course: write their structures from memory, explain the comparison, then check your explanation against your specification and a matching question. If you confused the structure, repair that first; adding a longer conclusion will not fix the starting error.

For qualitative chemistry, make separate columns for what you see, which species or change explains it, and the equation where required. Test the observations and equations specified by your board, then practise choosing a test from an unfamiliar question instead of only recognising a familiar flashcard.

Practical reasoning

Revise practical and data questions as reasoning tasks

For each practical you have studied, explain the purpose of the apparatus, the measurements, the calculation and the main limitation. Sketch the setup from memory, then check what each step achieves. This is written revision using your course materials, not a suggestion to repeat chemical experiments at home.

AQA’s physical chemistry content includes selecting titration data, identifying outliers, calculating mean titres and considering uncertainty from two burette readings. Practise explaining which results you would include in a mean and why. When a question asks about uncertainty or an improvement, identify the actual measurement and explain how your proposed change addresses its limitation; “improve accuracy” alone does not explain the method.

For an unfamiliar graph or table, identify the variables and units, describe the pattern with data, then link it to the chemistry. Distinguish the observation you can read from the data from the explanation you infer. Check whether your conclusion answers the question rather than merely describing the experiment.

In AQA 7405, practical knowledge is assessed in written exams, while the practical endorsement separately assesses observed practical competence. Match practical-question practice to your own board. For endorsement requirements and school arrangements, use our A-level Chemistry practical endorsement guide.

Feedback

Use mixed questions to test whether you can choose the method

After repairing a topic, mix it with earlier material. A set might include a mole calculation, an organic transformation and an explanation of bonding. Before solving each one, write what the question is asking and which evidence or relationship you need. This removes the clue provided by a worksheet headed “titration calculations”.

Progress from a single untimed question to a mixed set and then a complete paper under its printed time limit. Mark with the matching board, paper and year’s scheme. Read the full answer guidance, including alternatives, rather than assuming one model phrase is the only acceptable wording.

For each lost mark, record the exact error, the corrected reasoning and a retest task. “Units: used cm³ in n = cV; convert to dm³ before substitution; retry a new concentration question” is actionable. “Careless” is not. If you cannot tell why your explanation missed a mark, take the question and your answer to your teacher.

The error-log guide offers a reusable format. Keep the log shorter than the practice it produces: the goal is a successful later attempt without the correction in front of you.

Planning

Build a repeatable revision week

Choose sessions from the weaknesses your questions reveal. An adaptable pattern is one session repairing a physical calculation, another retrieving and drawing organic reactions, and another practising inorganic explanations and practical data. Add a short mixed set that returns to earlier mistakes. Give a weak area more attention without dropping the other areas altogether.

Within a session, begin with a brief closed-book attempt, check only what you need, then answer a fresh question and record the next retest. Return after a gap instead of repeating the same answer until it feels familiar. Active recall and spaced repetition explains this approach in more detail.

There is no fixed number of hours here that guarantees a grade. Adjust the workload to your other subjects and how much of the course you have been taught. Judge progress by whether you can choose and explain the method in a new question, not by the number of pages highlighted.

The EEF review of cognitive science approaches describes promising but variable evidence for retrieval and spacing. They support a revision routine; they do not replace learning how to apply the chemistry.

Support and clarity

Frequently asked questions

Straight answers to the questions people ask most often.

Can I use resources from another exam board?

They can provide extra practice in a shared concept, but compare the topic and level with your own specification first. Use your own board’s papers and mark schemes for assessment practice. A resource from another qualification may use different conventions or include content you do not need.

Should I memorise every mark-scheme answer?

Learn precise definitions, required observations and chemical terminology. For explanations, identify the reasoning that earns credit and practise applying it to a different question. Memorising a whole answer can hide a gap if you cannot explain why its steps follow.

What if I have only one day left?

Use recent mistakes to choose a small number of achievable repairs. Check core equations and units, retrieve reactions you repeatedly confuse, and attempt a short mixed set. Avoid spending the whole day making new notes. You cannot reliably replace a whole course of preparation in one day; focus on errors you can understand and correct, and leave time to rest.

Official guidance

1.
A-level Chemistry 7405 specification
AQA
2.
Physical chemistry subject content
AQA
3.
Organic chemistry subject content
AQA
4.
Inorganic chemistry subject content
AQA
5.
Scheme of assessment
AQA
6.
Practical assessment
AQA
7.
AS Chemistry Paper 2 June 2017 mark scheme
AQA
8.
AS and A Level Chemistry A H032 H432
OCR

Research and evidence

1.
Cognitive science approaches in the classroom: a review of the evidence
Education Endowment Foundation

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Revise from your exam specification

Frequently asked questions

Official guidance

Research and evidence