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A Level chemistry explained

Four specifications, three boards, one A Level. This page walks through what's on each paper, what's allowed in the exam, how the marks are split, and the specification codes if you need to check anything with the school.

Video coming soon The written guide below is complete and ready to read.

The exam boards compared

There are 4 A Level chemistry specifications in England. The boards do not teach different chemistry, what changes is how the course is organised. Your child’s school chooses which one to enter, and it may not be the same board it uses for other subjects. If you do not know which one, the school office will tell you.

At a glance

AQAEdexcel
Specification code74059CH0
Papers33
Length of each2 hr / 2 hr / 2 hr1 hr 45 min / 1 hr 45 min / 2 hr 30 min
Marks per paper105 / 105 / 9090 / 90 / 120
Total marks300300
Weighting35% / 35% / 30%30% / 30% / 40%
OCR A — Chemistry AOCR B — Chemistry B (Salters)
Specification codeH432H433
Papers33
Length of each2 hr 15 min / 2 hr 15 min / 1 hr 30 min2 hr 15 min / 2 hr 15 min / 1 hr 30 min
Marks per paper100 / 100 / 70110 / 100 / 60
Total marks270270
Weighting37% / 37% / 26%41% / 37% / 22%

What is on each paper

AQAEdexcel
Paper 1Inorganic and physical chemistryAdvanced Inorganic and Physical Chemistry
Paper 2Organic and physical chemistryAdvanced Organic and Physical Chemistry
Paper 3Across the specification, plus multiple choiceGeneral and Practical Principles in Chemistry
OCR A — Chemistry AOCR B — Chemistry B (Salters)
Paper 1Periodic table, elements and physical chemistryFundamentals of chemistry
Paper 2Synthesis and analytical techniquesScientific literacy in chemistry
Paper 3Unified chemistryPractical skills in chemistry

AQA does not give its papers names. What each paper covers is shown instead.

In the exam

AQAEdexcel
Data or formulae sheetProvidedProvided
Required practicals1216
Practical endorsementSeparate, does not affect the gradeSeparate, does not affect the grade
OCR A — Chemistry AOCR B — Chemistry B (Salters)
Data or formulae sheetProvidedProvided
Required practicals1212
Practical endorsementSeparate, does not affect the gradeSeparate, does not affect the grade

Every board sets a number of compulsory practicals, but they do not count them the same way, so the figures are not directly comparable: AQA lists required practicals, Edexcel core practicals, and OCR groups its into Practical Activity Groups. The practical endorsement is reported separately and does not contribute to the A level grade, but a student must complete it to be awarded the qualification.

How the marks are awarded

Whichever board your child sits, the exam rewards the same kinds of thinking in almost the same proportions. About a third of the marks are for straightforward recall (knowing the facts). A little over 40% are for applying that knowledge to a new question. The remaining quarter or so is for analysing, interpreting and evaluating (the harder skills).

Every board also sets a minimum for mathematical content: 20% of the marks in A Level chemistry are for maths at GCSE higher tier standard or above.

Codes, if you need to check with the school

AQAEdexcel
Specification code74059CH0
Ofqual number601/5731/8601/5646/6
Checked againstversion 1.2, July 2026Issue 3, February 2024
OCR A — Chemistry AOCR B — Chemistry B (Salters)
Specification codeH432H433
Ofqual number601/5255/2601/5371/4
Checked againstversion 3.1, May 2026version 4.1, May 2026

Every figure above was read from the board’s own specification on the date shown. Specifications change; if you are making a decision on one of these, confirm it with the school.