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Cambridge IGCSE

Chemistry 0620

Particles, bonding, reactions, acids and salts, the Periodic Table and organic chemistry, with a strong focus on experimental technique.

Syllabus version: 2026–2028 syllabusChecked against the Cambridge syllabusExam year 2027 is covered by the 2026–2028 syllabus.
Subject review complete (20 Oct 2026). All 40 Chemistry questions were re-solved and checked against the syllabus and Cambridge mark-scheme conventions, and their auto-marking was tested with correct and incorrect answers: 25 approved as written, 15 corrected.

Weighting by paper. Some papers are alternatives (for example Core or Extended, or practical or alternative to practical), so the figures add up to more than 100%.

  • Paper 2 Multiple Choice (Extended)30%
  • Paper 4 Theory (Extended)50%
  • Paper 5 Practical Test20%
  • Paper 6 Alternative to Practical20%
Original questions40
Topics covered12/12
Papers4
Mock papers3

What is assessed

4 components on the Extended tier. Question formats: multiple choice, short answer, structured, practical, alternative to practical.

Paper 2 Multiple Choice (Extended)Extended
45 min40 marksWeighting 30%

40 compulsory four-option multiple-choice items on the Core and Supplement content, testing AO1 and AO2; grades A* to G.

What the paper looks like

40 one-mark, four-option items in 45 minutes on Core and Supplement content. Expect more mole calculations, bond energies, equilibrium shifts, half-equations and oxidation numbers than Paper 1. Distractors are built on common slips (wrong mole ratio, missing ×2, reversed sign), so check each step.

Multiple choicePeriodic Table printed in the paper; calculator allowed
Checked against the Cambridge syllabus
Paper 4 Theory (Extended)Extended
1 h 15 min80 marksWeighting 50%

Compulsory short-answer and structured questions on the Core and Supplement content, testing AO1 and AO2; grades A* to G.

What the paper looks like

80 marks in 1 hour 15 minutes, all compulsory, typically six or seven structured questions of 5–17 marks. Includes multi-step mole calculations (show working), symbol and ionic equations with state symbols, half-equations, dot-and-cross diagrams, displayed formulae and explanations using particles, bonding, collision theory or equilibrium.

Short answerStructuredPeriodic Table printed in the paper; calculator allowed
Checked against the Cambridge syllabus
Paper 5 Practical TestCore & Extended
1 h 15 min40 marksWeighting 20%

Laboratory practical test (AO3) based on the experimental skills in Section 4: a quantitative experiment, a qualitative analysis exercise and a planning question.

What the paper looks like

40 marks in 1 hour 15 minutes in the laboratory. Usually a quantitative experiment (about 20 marks: readings in a table, a graph, a calculation and evaluation), a qualitative analysis exercise using the notes for qualitative analysis (about 14 marks), and a short planning question (about 6 marks).

PracticalNotes for use in qualitative analysis provided; calculator allowed
Checked against the Cambridge syllabusNo questions for this paper yet
Paper 6 Alternative to PracticalCore & Extended
1 h40 marksWeighting 20%

Written paper (AO3) on the same experimental skills as Paper 5, using supplied readings, diagrams and observations instead of laboratory work.

What the paper looks like

40 marks in 1 hour with no lab work. Typically a short apparatus or technique question, a long data question (reading burettes, thermometers or stop-watches from diagrams, completing a table, plotting a graph, interpolating and evaluating), a qualitative analysis question using the supplied notes, and a 6-mark planning question.

Alternative to practicalNotes for use in qualitative analysis provided; calculator allowed
Checked against the Cambridge syllabus

Assessment overview

From the 2026–2028 syllabus. Checked against the Cambridge syllabus

Core
Paper 1Paper 3Paper 5Paper 6
Papers 1 and 3, plus either Paper 5 or Paper 6. Grades C to G available.
Extended
Paper 2Paper 4Paper 5Paper 6
Papers 2 and 4, plus either Paper 5 or Paper 6. Grades A* to G available.
Assessment objectiveIGCSE weighting
AO1 Knowledge with understanding50%
AO2 Handling information and problem-solving30%
AO3 Experimental skills and investigations20%
Changes in this syllabus version
  • Version 2 (published August 2026): the Assessment overview page was updated; the subject content is unchanged.
  • No substantial changes affecting teaching compared with the 2023–2025 syllabus: the same six papers, durations, marks and weightings.
  • The “Equality and inclusion” section of the syllabus was rewritten as “Accessibility and equality”.
  • Textbooks endorsed for examination from 2023 remain suitable.
Command words used in Chemistry papers (22)
Analyse
examine in detail to show meaning, picking out elements and how they relate
Calculate
work out an answer from the given facts, figures or information
Compare
say or comment on how things are alike and/or different
Consider
review the information given and respond to it
Contrast
say or comment on how things are different
Deduce
reach a conclusion from the information available
Define
give the precise meaning
Demonstrate
show how, or give an example
Describe
state the points of a topic or give its main features and characteristics
Determine
establish an answer using the information available
Discuss
write about an issue or topic in depth, in a structured way
Evaluate
judge or calculate the quality, importance, amount or value of something
Examine
investigate closely and in detail
Explain
give purposes or reasons, make relationships clear, say why and/or how, supported by evidence
Give
produce an answer from a given source or from recall
Identify
name, select or recognise
Justify
support a case with evidence or argument
Predict
suggest what may happen, based on the information available
Show (that)
give structured evidence that leads to a stated result
Sketch
make a simple freehand drawing showing the key features, with care over proportions
State
express in clear terms
Suggest
apply knowledge to a situation with several valid answers, putting forward proposals or considerations
Examiner guidance from recent reports (13)
States of matter. When asked for the state at a given temperature, compare the temperature with BOTH the melting point and the boiling point, and take care with negative values: −20 °C is higher than −117 °C. In diffusion questions, the gas with the lower Mᵣ moves faster.
Atoms, elements and compounds. Say which particles you mean. Ionic compounds have strong attraction between oppositely charged ions; simple molecular substances have weak forces BETWEEN molecules (the covalent bonds themselves are strong). For conductivity, name the mobile charge carriers: delocalised electrons that move (metals, graphite) or ions that move (molten or aqueous ionic compounds).
Stoichiometry. Write symbols with the correct capital and small letters (Na, not NA or na) and never show charges inside the formula of a compound. In empirical formula work keep the ratio exact: 1 : 2.5 must be doubled to 2 : 5, not rounded. Show every step of a mole calculation so method marks can be given.
Electrochemistry. Name the products, not the electrodes. Half-equations need electrons on the correct side (gained at the cathode, lost at the anode), balanced charges and molecular formulae such as H₂, Cl₂ and O₂. Learn the observations for each electrolyte: bubbles, a pink-brown coating, a fading blue colour.
Chemical energetics. Exothermic: the surroundings get hotter and ΔH is negative. Endothermic: the surroundings get colder and ΔH is positive. In bond-energy calculations, total the bonds broken and the bonds made separately, then ΔH = energy in − energy out; always include the sign and kJ/mol.
Chemical reactions. For equilibrium, write “the rates of the forward and reverse reactions are equal” and “the concentrations no longer change” — not “the concentrations are equal”. Pressure arguments must compare the number of moles of gas on each side. For rate, link each change to the frequency of collisions and, for temperature, to the proportion of particles with at least the activation energy.
Acids, bases and salts. Learn the solubility rules: all nitrates and all sodium, potassium and ammonium salts are soluble. For an insoluble salt, filter, then wash and dry the residue; for a soluble salt, use excess solid, filter off the excess, then crystallise the filtrate. Precipitation ionic equations have aqueous ions on the left and a solid on the right.
The Periodic Table. Answer the trend that is asked for (melting point, density or reactivity) and use the data in the table to keep predictions realistic. Do not confuse a Period (row) with a Group (column). Explain similar reactions within a group by the same number of outer-shell electrons.
Metals. Sacrificial protection works because zinc is more reactive than iron and loses electrons in preference; a barrier alone fails once it is scratched. In blast furnace questions name substances precisely: coke, limestone, calcium silicate (slag) and silicon(IV) oxide as the acidic impurity.
Chemistry of the environment. Match each pollutant to its own source and effect: CO from incomplete combustion (toxic), SO₂ from sulfur in fossil fuels (acid rain), particulates (respiratory problems and cancer), nitrogen oxides from car engines (acid rain, smog). For photosynthesis mention both light energy and chlorophyll.
Organic chemistry. Displayed formulae must show every atom and every bond, including O–H. Straight-chain C₄ alkenes need a locant: but-1-ene or but-2-ene. A repeat unit of an addition polymer has no C=C and has extension bonds; a molecular formula is C₅H₁₀, not (CH₂)₅. Spell key terms correctly: fermentation, chromatography, galvanising.
Experimental techniques and chemical analysis. Tests are required knowledge on Papers 3 and 4 (the qualitative analysis notes appear only on Papers 5 and 6). Record observations, not conclusions: “effervescence” rather than “gas given off”, “white ppt.” rather than “cloudy”, and give the gas test with its result.
Experimental techniques and chemical analysis. Record every reading from one instrument to the same resolution: burette readings to 2 d.p. (0.00, not 0), thermometer readings to the nearest 0.5 °C (21.0, not 21). Plot points to within half a small square and draw a smooth curve if the points curve. In planning answers, describe what each piece of apparatus is used for.

Topic map

Practice types

Free sample questions

The table shows the melting points and boiling points of four substances. [table] Which substance is a gas at…
The table shows the melting points and boiling points of four substances.
substancemelting point / °Cboiling point / °C
W−210−196
X−759
Y44280
Z−11718
Which substance is a gas at 25 °C but a liquid at −20 °C?
  1. W
  2. X
  3. Y
  4. Z

Answer: D. Z

A substance is a liquid between its melting point and its boiling point. Z boils at 18 °C, so it is a gas at 25 °C, and −20 °C lies between −117 °C and 18 °C, so it is a liquid there. X is a liquid at 25 °C (and a solid at −20 °C); W is a gas at both temperatures; Y is a solid at both.

Equal amounts of four gases are released together at one end of a long glass tube at the same temperature.…
Equal amounts of four gases are released together at one end of a long glass tube at the same temperature. Which gas is detected first at the other end?
  1. carbon dioxide, CO₂
  2. chlorine, Cl₂
  3. methane, CH₄
  4. nitrogen dioxide, NO₂

Answer: C. methane, CH₄

At the same temperature, particles with a lower relative molecular mass move faster on average, so they diffuse faster. Mᵣ: CH₄ = 16, CO₂ = 44, NO₂ = 46, Cl₂ = 71. Methane has the lowest Mᵣ and arrives first.

FAQs

Are these official 0620 past-paper questions?

No. They are original questions written to match the Chemistry syllabus topics. Official past papers are available to schools through Cambridge.

Why choose an exam year?

Cambridge updates syllabuses periodically. Your exam year selects the matching configuration so topics and components follow the right version.

Is a calculator allowed?

In this configuration a scientific calculator is permitted for the listed papers. Check your syllabus for the exact rule.