Exam guide

2. Paper structure (from the cover pages)

Weighting (inferred from the threshold sheets):

• 2023 onwards: 40 (P1) + 80 (P2) + 40 (P3/4) raw marks make a weighted 200. This fits P1 ×1.5 (30 %), P2 ×1.25 (50 %) and P3/4 ×1 (20 %).
• 2022: 145 fits 40 + 75 + a practical scaled to 30.

Other notes:

• Candidates take P1 + P2 + either P3 or P4. The threshold sheets list options AX (11, 21, 31) and BX (11, 21, 41).
• June 2026 also lists a Component 50 (90 marks) route. No local paper exists for it, so it is not analysed here.

What changed from 2022 to 2023 onwards, as seen in the papers:

• Section B choice removed and P2 lengthened.
• P4 cut from 60 to 40 marks and aligned with P3.
• A planning question added to every practical paper.
• New-syllabus content now appears regularly: hydrogen–oxygen fuel cells, bond-energy calculations, reaction-pathway diagrams, oxidation numbers, gas pressure/volume ideas, Rf values, sustainability and plastics disposal, and "describe and explain" rate questions.
• Old-syllabus extras have faded:
  • the uses of SO2 and sulfuric acid, and the sulfur chemistry around the Contact process;
  • hydrolysis of fats, proteins and starch;
  • long blast-furnace and electrolysis-of-alumina essays.

3. Topic list (12 syllabus topics, subtopics confirmed against the questions)

4. Topic weights

4a. Marks per topic per session, theory papers (P1 + P2, variant 1)

4b. % share by component, 2022 against 2023–26

Paper 1 is a fixed blueprint. Since 2023 every MCQ paper has roughly the same spread:

• 1–2 items on states of matter;
• 3–6 on atoms and bonding;
• 4–6 on stoichiometry;
• 1–2 on electrochemistry;
• 1–3 on energetics;
• 2–7 on rates, equilibrium and redox;
• 2–3 on acids and salts;
• 2–4 each on the Periodic Table and on metals;
• 2–3 on the environment;
• 5–7 on organic chemistry;
• 3–4 on experimental techniques.

Every topic is tested in every session.

4c. Practical papers (P3 / P4, 2023–26, average marks per paper out of 40)

About 85 % of practical marks are experimental skills, not topic content. The quantitative experiment rotates:

• an acid–base titration (2022, June 2023, Nov 2024, June 2025);
• a thermometric titration (Nov 2023, Nov 2025);
• metal displacement with a temperature rise (June 2024);
• rate against concentration (June 2026).

5. Banker topics

These subtopics appear in P1 or P2 in all 9 sessions, and in all 7 sessions since 2023:

Close behind, at 7–8 of 9 sessions:

• formulae and equations (including ionic);
• gas volumes at r.t.p.;
• diffusion;
• metallic bonding;
• energy profiles;
• the Haber/Contact conditions;
• transition elements;
• the reactivity series;
• air pollutants and catalytic converters;
• cracking and petroleum fractions;
• alkenes;
• alcohols (fermentation and hydration).

6. Rarely tested

These appear in P1/P2 in 4 or fewer of the 9 sessions, or carry very few marks:

• physical vs chemical change (1 session);
• composition of air (2);
• structure–property comparison tables (3);
• relative mass as a standalone item (4, although Mr is used in every calculation);
• electroplating / industrial electrolysis (4);
• fertilisers (NPK) (4);
• titration technique in theory papers (4; it is heavily tested in the practicals instead).

Moderate (5–6 sessions), usually as one MCQ item:

• Group I;
• Group VII;
• noble gases;
• fuel cells;
• chromatography;
• alloys;
• corrosion;
• percentage yield.

Since 2023, Metals in Paper 2 has shrunk to 0–9 marks (0 in June 2024).

7. Trends (2022 against 2023–26)

• Organic chemistry is the largest and growing topic. It rose from 18.8 % to 23.8 % of Paper 2 and peaked at 27/80 in Nov 2025. Expect 17–27 marks of organic chemistry on P2, plus 5–7 MCQ items.
• Energetics and electrochemistry are up in P2. Bond-energy calculations, reaction-pathway diagrams and fuel-cell items now appear in most sessions; in 2022 they were close to zero.
• Stoichiometry and Metals are down as a share of the theory papers. Stoichiometry is still in every paper: about 9–16 marks on P2 and 4–6 MCQ items. In 2022, Metals had long blast-furnace and aluminium questions; since 2023 it is mostly tested in the MCQ.
• Rates and equilibrium are steady at about 13 % of P2. The new papers like the "describe and explain" format (2 marks for the effect, 2 for the explanation).
• Chemical reactions fell in 2025–26 P1 (from 6–7 items to 2–3). Treat this as possibly a blip, not a trend.
• Practicals are now predictable:
  • P3 and P4 share the same three-part structure;
  • qualitative analysis is about 14–17 marks;
  • a quantitative experiment with a graph or titre table;
  • a 6-mark plan.

Planning contexts so far:

- baking powder freshness;
- preparing ammonium sulfate;
- % mass loss on heating BaCO3;
- % copper in an alloy;
- separating MgO from BaSO4;
- comparing heat from methanol and ethanol;
- the salt-and-ice temperature drop;
- finding ammonia concentration.

8. Recurring question styles (P2, approximate marks per paper from keyword matching)

Typical openers and set pieces:

• Q1 is almost always a "choose from this list" item (5–6 one-mark parts): oxides, salts, compounds or atoms identified by a property, a test or a use.
• A "describe and explain" rate or equilibrium question is in every paper.
• Mole calculations usually come in 2–3 steps, for example a limiting reactant, then a mass of product, then % yield.
• MCQ styles:
  • "which statements 1, 2, 3 are correct";
  • two-statement items (is statement 2 an explanation of statement 1?);
  • gap-fill rows ("words to complete gaps 1 and 2").

9. Common mistakes (examiner reports, June 2022, Nov 2022, June 2023)

Rates and equilibrium

• Mixing up rate and equilibrium: using collision theory to explain an equilibrium shift, or the position of equilibrium to explain a rate.
• Saying "more collisions" without "more frequent collisions" (for concentration or pressure), or without "more collisions with energy ≥ Ea" (for temperature).
• Treating activation energy as a maximum energy, or drawing Ea from the products.
• Saying a catalyst gives particles more energy.

Equations

• Weak balancing, especially ionic and half-equations.
• Electrons on the wrong side of a half-equation.
• Ions left in the products: "lead(II)" instead of lead, or the ions that move instead of the substances formed.
• Writing NH4 for ammonia; forgetting that H2 and Cl2 are diatomic.

Calculations

• Comparing masses instead of moles to find the limiting reactant.
• Using 16 instead of 32 for O2.
• Counting one N instead of two in NH4NO3.
• Wrong significant figures.
• Untidy working that loses error-carried-forward marks.
• In practicals: ignoring the mole ratio, swapping the pipette and titre volumes, and missing a dilution step (for example, 5 cm³ made up to 250 cm³).

Organic chemistry

• Carbons with five bonds; –O–H– in structures.
• Wrong ester names (the alcohol and acid parts swapped or mis-assigned).
• Drawing polymer linkages without continuation bonds.
• Branched isomers drawn as bent unbranched chains.
• Confusing hydration conditions with fermentation conditions.

Bonding

• Intermolecular forces described as "between atoms" or "between bonds".
• Contradictory particle descriptions ("far apart but closely packed").
• Metallic-structure diagrams without labels or with ions far apart.
• An alloy described as a compound.

Environment

• Confusing the greenhouse effect with ozone depletion.
• Saying UV is "reflected".
• Confusing fertilisers with pesticides.

Tests and observations

• Leaving out the word "precipitate".
• Swapping the Fe2+ and Fe3+ colours.
• Writing "white solution".
• Giving explanations instead of observations.
• Not knowing what iodine looks like or the colour of a sodium flame.

Practical planning

• Not following the bullet list in the planning question.
• Proposing non-laboratory methods.
• Heating to dryness instead of to a saturated solution when crystallising.

10. Grade thresholds

10a. Overall (weighted). 2022 is out of 145; 2023 onwards is out of 200.

10b. Component thresholds, variant 1 (grade A / grade C)

Reading the thresholds:

• A* needs about 80–87 % of the weighted total.
• A needs about 65–73 %.
• C needs only about 33–40 %. On Paper 2, a C is about 22–25 out of 80 (under a third), so steady marks across every question matter more than finishing the hard parts.
• Nov sessions run 3–8 marks higher than June.

11. Revision priorities for Oct/Nov 2026 and 2027 candidates

1. Organic chemistry first (about 21 % of theory marks, and rising). Practise:
   • naming and drawing alkanes, alkenes, alcohols, acids and esters, both ways round (name ↔ structure);
   • structural isomers;
   • substitution with Cl2/UV and addition with Br2, H2 and steam, with their conditions;
   • fermentation compared with hydration of ethene;
   • cracking equations;
   • addition repeat units and condensation linkages (amide/ester), including proteins and plastics disposal.
2. Moles every paper: reacting masses, limiting reactant, gas volume (24 dm³), concentration, empirical/molecular formula, % composition and % yield, and Avogadro-number questions. Always show working, using moles, not masses.
3. Rates and equilibrium, "describe and explain": learn the exact collision-theory wording (frequency of collisions; proportion of collisions with energy ≥ Ea). Separately, learn Le Chatelier answers for temperature and for pressure (counting moles of gas). Do not mix the two.
4. Equations: symbol equations with state symbols; ionic equations (neutralisation, displacement, precipitation); electrode half-equations with electrons on the correct side.
5. Bonding and structure: dot-and-cross diagrams for small molecules and ionic compounds; why ionic, simple molecular, giant covalent and metallic substances have the properties they do.
6. Electrochemistry and energetics (new-syllabus favourites): electrolysis products for molten, concentrated aqueous and dilute aqueous electrolytes; CuSO4 with copper vs inert electrodes; fuel cells; reaction-pathway diagrams (labelled ΔH and Ea arrows); bond-energy calculations.
7. Practical (P3 or P4, 20 % of the grade):
   • Learn the qualitative-analysis tables by heart: cation colours with NaOH and NH3, including the excess behaviour; anion tests; gas tests; flame colours. Always write "precipitate".
   • Practise titration tables: concordant titres, average, 2 d.p. readings.
   • Practise thermometric graphs with two best-fit lines.
   • Rehearse the 6-mark plan template: apparatus, quantities, method steps, what to measure, how to process the result, and a fair-test or safety point.
8. Quick-win MCQ topics (one item each, every session): diffusion rates (Mr), isotope and ion particle counts, types of oxide, Group I/VII/VIII trends, transition-element properties, alloys, rust prevention, water treatment, pollutant effects, chromatography Rf, and choosing apparatus.
9. Lower priority: physical vs chemical change, composition of air, NPK details and electroplating. Learn the key facts, but do not over-invest.