Measured on 150 real questions
What actually comes up in ESAT Chemistry
Topic frequency for ESAT Chemistry, measured on 150 real past-paper questions from the test’s predecessor papers.
Two thirds of ESAT chemistry is physical and quantitative chemistry. Organic chemistry is 4.7%.
ESAT Chemistry has the most lopsided distribution of any module we measured, and it is lopsided in a direction that catches A-level students out. School chemistry gives organic, inorganic and physical roughly equal billing. The papers do not.
We tagged 150 questions from NSAA Section 1 (2016 to 2023) that fall inside the current ESAT specification. Each question carries one topic tag, so the shares below add to 100%.
Topic frequency
Every ESAT Chemistry topic, by how often it actually appeared.
150 questions, 5 topics. Each question carries exactly one topic tag, so these shares add to 100% and can be read as shares of a paper. The 95% confidence interval is the range the true share plausibly sits in given this sample size.
| # | Topic | Questions | Share | 95% CI |
|---|---|---|---|---|
| 1 | Physical and quantitative chemistry | 100 / 150 | 66.7% | 58.8-73.7% |
| 2 | Periodicity and inorganic | 16 / 150 | 10.7% | 6.7-16.6% |
| 3 | Redox and electrochemistry | 14 / 150 | 9.3% | 5.6-15.1% |
| 4 | Atomic structure and bonding | 13 / 150 | 8.7% | 5.1-14.3% |
| 5 | Organic chemistry | 7 / 150 | 4.7% | 2.3-9.3% |
Evidence base: ENGAA and NSAA Section 1, 2016-2023, filtered to the current ESAT specification.
Where the data disagrees with the revision guides
Organic is not the main event
Mechanisms, reagents and synthesis routes take up a large share of A-level chemistry teaching time and of most students’ revision anxiety. In the tagged papers, organic chemistry accounted for 7 questions out of 150. The 95% confidence interval runs from 2.3% to 9.3%, so even at the top of the range it stays a minor strand. Time moved from organic to quantitative work is, on this evidence, time well moved.
What this means for your revision
Four things the numbers say about ESAT Chemistry.
- 01
Physical and quantitative chemistry is 66.7% of the module. Moles, energetics, equilibria, rates and the calculations that go with them are the module.
- 02
Everything else fights over the remaining third: periodicity and inorganic (10.7%), redox and electrochemistry (9.3%), atomic structure and bonding (8.7%) and organic (4.7%).
- 03
Organic chemistry at 4.7% is roughly one question in twenty-one. It is the single easiest place to over-invest.
- 04
Because the module is quantitative and there is no calculator, arithmetic under time pressure is a chemistry skill here, not a maths one.
Free resource
The recall sheet these numbers came from.
Neither the ESAT nor the TMUA gives you a formulae booklet or a calculator, so everything on the specification is a memorisation liability. Our recall sheet lists every formula, rule and technique for all seven modules, each one tied to the spec clause that requires it, with the measured frequency beside it. It is free.
Get the free ESAT recall sheetMethod and coverage
How this was measured, and what it does not cover.
The corpus is 1,250 real past-paper questions across all seven modules, of which 150 are ESAT Chemistry - and every percentage on this page is out of that 150, not out of the full corpus.
Not one question we wrote ourselves is counted. Our own question bank is excluded on purpose: treating questions we authored as evidence of what Cambridge asks would be circular.
What the corpus holds
| Paper | Years | Published | Held |
|---|---|---|---|
| ENGAA | 2016-2023 | 362 | 315 |
| NSAA | 2016-2023 | 680 | 575 |
| TMUA | 2016-2023 + early specimen | - | 360 |
What it does not hold
A frequency table is a claim about a denominator, so a gap in the denominator biases every percentage above. These are the gaps, audited 2026-08-17. The first two matter to a candidate; the rest are recorded for completeness.
TMUA 2024 onwards
TMUA figures cover the 2016-2023 sittings and the early specimen. The 2024 and later sittings are not held.
This is the one gap that touches a LIVE test. TMUA percentages describe the Cambridge-era papers, which are the closest available evidence but are not the most recent sittings a current candidate will have seen.
ESAT, all years
No live ESAT paper has ever been released. Only the 2024 specimen and sample exist, and the sample has no answer key.
This is the whole reason ENGAA and NSAA stand in as the evidence base: they are ESAT's direct predecessors, filtered to the current ESAT specification.
NSAA 2016-2019 · 72 questions
NSAA Section 1 had a fifth part (E, Advanced Maths and Physics) in 2016-2019 which this corpus does not carry.
NSAA papers contain 680 questions. 608 are held here, and 575 of those fall inside the current ESAT specification - 575 is the number every ESAT percentage on this page is drawn from. Because Part E is out of ESAT scope, excluding it makes the ESAT-relevant percentages MORE accurate, not less: it would otherwise dilute every count with material ESAT never tests.
ENGAA and NSAA, all years
Only Section 1 papers are held. Neither test's Section 2 is in the corpus.
No effect on ESAT-relevant frequency: the format being measured does not exist in ESAT.