Cambridge IGCSE Chemistry (0620) Past Papers: Grade Thresholds and Examiner Report Notes

This page is a guide to Cambridge IGCSE Chemistry (0620) past papers from March 2020 to November 2025. For each series you get the grade thresholds, copied from Cambridge’s grade-threshold documents, and a short account of what the examiners saw, written by us from Cambridge’s Principal Examiner Reports for Teachers. We do not host any papers. Every paper, mark scheme and report is on Cambridge’s own site, linked below.

Where to get the official papers

• Cambridge IGCSE Chemistry (0620) syllabus page
• Cambridge IGCSE Chemistry (0620) past papers page

Cambridge publishes recent papers, mark schemes, examiner reports and grade thresholds on the syllabus’s past-papers page; older series are available to schools through the School Support Hub.

Use the three documents together. Sit the paper first, under timed conditions. Mark it strictly with the mark scheme, which tells you what each mark needs. Then read the examiner report for that paper: it tells you why answers that looked right still lost marks. Our notes for each series below are a quick way into that report.

Check which syllabus a paper was set on. The current syllabus is the 2026–2028 version. Papers from March 2023 to November 2025 were set on the 2023–2025 syllabus, and the examiner reports for 2023 and 2024 say some newer content was still unfamiliar to candidates. Papers from 2020 to 2022 were set on the version examined before 2023. For any older paper, check the syllabus version on the paper’s front cover against the current syllabus before you rely on a question.

Series index

Series	Papers (components) examined	Examiner report notes	Grade thresholds
November 2025	11–13, 21–23, 31–33, 41–43, 51–53, 61–63	Summarised (the report has no section for Paper 51)	Yes
June 2025	11–13, 21–23, 31–33, 41–43, 51–53, 61–63	Summarised	Yes
March 2025	12, 22, 32, 42, 52, 62	Summarised	Yes
November 2024	11–13, 21–23, 31–33, 41–43, 52–53, 61–63	Summarised	Yes
June 2024	11–13, 21–23, 31–33, 41–43, 51–53, 61–63	Summarised	Yes
March 2024	12, 22, 32, 42, 52, 62	Summarised	Yes
November 2023	11–13, 21–23, 31–33, 41–43, 52–53, 61–63	Summarised	Yes
June 2023	11–13, 21–23, 31–33, 41–43, 51–53, 61–63	Summarised	Yes
March 2023	12, 22, 32, 42, 52, 62	Summarised	Yes
November 2022	11–13, 21–23, 31–33, 41–43, 51–53, 61–63	Summarised (Paper 51 had too few candidates for a report)	Yes
June 2022	11–13, 21–23, 31–33, 41–43, 51–53, 61–63	Summarised	Yes
March 2022	12, 22, 32, 42, 52, 62	Summarised	Yes
November 2021	11–13, 21–23, 31–33, 41–43, 51–53, 61–63	Summarised (Paper 51 had too few candidates for a report)	Yes
June 2021	11–13, 21–23, 31–33, 41–43, 51–53, 61–63	Summarised (Paper 13 had too few candidates for a report)	Yes
March 2021	12, 22, 32, 42, 52, 62	Summarised	Yes
November 2020	11–13, 21–23, 31–33, 41–43, 51–53, 61–63	Summarised	Yes
June 2020	Cancelled by Cambridge because of COVID-19	Not summarised here	Not summarised here
March 2020	12, 22, 32, 42, 52, 62	Summarised	Yes
November 2019	See the official past papers page	Not summarised here	Not summarised here
June 2019	See the official past papers page	Not summarised here	Not summarised here
March 2019	See the official past papers page	Not summarised here	Not summarised here

Papers 1 and 2 are multiple choice (Core and Extended), Papers 3 and 4 are theory (Core and Extended), Paper 5 is the Practical Test and Paper 6 is the Alternative to Practical. In the threshold tables, each row is one option: the set of components a candidate sat, out of the maximum mark shown. Rows built on Papers 1 and 3 are Core and stop at grade C; rows built on Papers 2 and 4 are Extended and run from A* downwards. Series from 2026 onwards are not summarised here yet.

What examiners keep saying

These are the errors that come back series after series. Each is grouped under the syllabus topic it belongs to.

States of matter

• Particle arrangement, separation and motion get mixed up, or the answer describes the whole substance instead of its particles. Some candidates even read “separation of particles” as a way of separating a mixture. (November 2025, June 2025, March 2025, November 2024, March 2024, November 2023, November 2022, June 2022, November 2021, March 2021)
• On a cooling or heating curve, candidates forget that the temperature stays level while the state changes. (March 2025, March 2023)

Atoms, elements and compounds

• Electron counts for an ion ignore its charge, so the ion gets the atom’s configuration. (March 2025, March 2022, June 2021)
• Metallic bonding is described as if it were ionic, and electrons or ions are called “free” instead of mobile. (November 2025, June 2024, November 2023, November 2022, June 2022, March 2022)
• A covalent bond is defined loosely. The definition needs one shared pair of electrons between two atoms. Candidates also say boiling a simple molecular substance breaks the covalent bonds inside the molecules. (June 2025, November 2024, June 2024, March 2024, November 2021, June 2021)
• Isotopes are defined without saying they are atoms. (November 2025, June 2023, November 2020)

Stoichiometry

• A 1 : 1 mole ratio is assumed instead of reading the ratio from the equation, and units are not converted between cm³ and dm³. (November 2025, June 2025, November 2024, November 2022, June 2022, November 2021, November 2020)
• Ionic equations keep the spectator ions, or the full equation is written out for a precipitation or halogen displacement. (June 2025, March 2025, November 2023, March 2024, November 2022, November 2021, June 2021, March 2020)

Electrochemistry

• Aqueous electrolytes are treated as if molten, the electrodes are swapped, or an ion such as chloride is given where the element is formed. (November 2025, March 2025, November 2024, June 2024, November 2023, June 2023, June 2021, March 2021)
• Conduction through an electrolyte is put down to electrons rather than mobile ions, and half-equations have the electrons on the wrong side. (March 2025, November 2024, June 2024, June 2023, November 2022, June 2022, March 2022, March 2020)

Chemical energetics

• Exothermic and endothermic are swapped, and energy diagrams are described without comparing the energy of reactants with that of products. (March 2025, November 2024, June 2024, November 2023, March 2023, November 2022, June 2022, March 2022)

Chemical reactions

• Rate is explained as “more collisions” instead of more frequent collisions, with no mention of the share of collisions with energy above the activation energy. Rate and time taken are also confused. (June 2025, November 2025, March 2025, November 2024, November 2023, June 2023, March 2023, November 2022, November 2021, March 2021, March 2020)
• At equilibrium, candidates say the concentrations are equal (they stay constant) and leave out that the forward and reverse rates are equal. Shifts are described with an “endothermic side” instead of a direction. (June 2025, June 2024, March 2024, November 2023, June 2023, November 2022, November 2021, June 2021, March 2020)
• Oxidation numbers are written without a sign, as ion charges or as Roman numerals. (June 2025, November 2024, June 2024, November 2023, March 2023)

Acids, bases and salts

• Salt preparation goes wrong at the same steps: excess solid not filtered off, the solution heated to dryness instead of to the crystallisation point, an insoluble salt crystallised, or the residue not washed and dried. (June 2025, November 2024, June 2024, November 2023, June 2023, March 2023, November 2022, March 2022, November 2020)
• The solubility rules are not known, so candidates pick the wrong method and the wrong state symbols. (November 2025, November 2024, June 2024, March 2024)

Metals

• The roles of coke, limestone and carbon monoxide in the blast furnace are muddled, and alloys are treated as compounds. (November 2025, November 2024, March 2024, November 2023, March 2023, June 2021, March 2020)

Chemistry of the environment

• Pollutant sources and effects are vague, and ways to cut sulfur dioxide are not known. (June 2024, March 2024, June 2023, March 2023, November 2022, March 2022, November 2021, June 2021)

Organic chemistry

• Displayed formulae leave out the O–H bond, give carbon three or five bonds, or draw monomers with continuation bonds. (June 2025, March 2025, June 2024, March 2024, November 2023, June 2023, March 2023, November 2022, June 2022, March 2022, November 2021, March 2021, November 2020, March 2020)
• Fermentation conditions are given for the hydration of ethene, or the other way round. (November 2025, June 2025, March 2025, November 2024, March 2020)
• Unsaturation is described as “a double bond” without saying it is between carbon atoms, and names leave out the position number. (June 2025, March 2025, June 2024, November 2024, March 2024, June 2023)

Experimental techniques and chemical analysis

• Ion and gas tests are flagged in every series: wrong reagent, wrong colour, a gas named but not tested, or a positive result claimed for a negative test. (every series from March 2020 to November 2025)
• “A gas is given off” is written as an observation. Examiners want what you see, such as fizzing. (June 2025, November 2025, March 2025, June 2023, June 2021, March 2021, November 2020)
• Graphs have awkward scales, dot-to-dot or straight lines through curved data, and missing units. Readings are recorded to mixed decimal places. (November 2025, June 2025, March 2025, November 2024, June 2024, November 2023, March 2023, November 2022, March 2022, June 2021, November 2020, March 2020)

Our revision notes for the topics above: states of matter, bonding, formulae, equations and the mole, electrolysis, energetics, rates of reaction, redox, acids, bases and salts, organic chemistry, identification tests and practical techniques.

Exam technique the reports repeat

• Give one answer when one is asked for. A wrong extra answer cancels a right one.
• An observation is something you can see: fizzing, a colour change, a precipitate and its colour. For a gas, give the test and its result.
• In planning questions, do not list aims, apparatus and variables. Write a method that says what each piece of apparatus measures, with quantities, and how the result gives the conclusion.
• Tick off each mark allocation. Parts answered on a diagram or graph have no answer lines and are often left blank.
• Show working, give a relative formula mass as a number, and finish the arithmetic. Fractions and unworked sums do not score.
• Plot graphs with crosses in pencil on scales of 1, 2 or 5 per division that fill at least half the grid. Draw a smooth curve or a ruled line, not dot-to-dot.

November 2025

This series drew on atomic structure and bonding, the blast furnace, electrolysis, water treatment, fractional distillation, the two industrial routes to ethanol, polymers, making salts and the qualitative tests. Atomic structure, nuclide notation, bonding and reading tables and graphs went well across the papers. Across the multiple-choice and theory reports, though, the weak spots were ion and gas tests, the solubility rules, and organic reactions and polymerisation. Better answers quoted definitions exactly, described real observations, handled mole ratios and unit changes, and kept time, rate and yield apart. Weaker answers gave vague uses, swapped the electrodes, mixed up fermentation with steam hydration and skipped diagram parts.

Where marks were lost

• Papers 31–33: anion, hydrogen and flame tests often not known at all, and parts left blank. Chlorine’s job in water treatment given as removing microbes rather than killing them.
• Papers 41–43: isotopes defined without the word atoms; near-miss definitions of saturated solution and oxidising agent; unbalanced equations and half-equations.
• Papers 21–23: copper electrodes treated as inert; the fuel cell confused with electrolysis; oxidation number mixed up with the charge on a compound ion.
• Papers 52 and 62: titres not found by subtracting the initial reading; “no change” reported when a coloured reagent tinted the solution; plans that were lists instead of a measured method.
• Papers 53 and 63: not seeing that the same energy warms a larger volume by less; straight lines forced through curves.

Grade thresholds – November 2025

Option	Components	Max	A*	A	B	C	D	E	F	G
BX	21, 41, 51	200	158	132	106	80	67	54	43	32
BY	22, 42, 52	200	153	127	101	76	63	50	39	28
BZ	23, 43, 53	200	163	137	111	85	72	60	49	38
CX	21, 41, 61	200	159	133	107	82	69	56	45	34
CY	22, 42, 62	200	153	127	101	76	63	51	40	29
CZ	23, 43, 63	200	163	137	111	86	73	61	50	39
FY	12, 32, 52	200	–	–	–	100	84	69	53	37
FZ	13, 33, 53	200	–	–	–	102	86	71	56	41
GX	11, 31, 61	200	–	–	–	105	89	73	58	43
GY	12, 32, 62	200	–	–	–	100	85	70	54	38
GZ	13, 33, 63	200	–	–	–	103	87	72	57	42

Official documents: past papers, mark schemes and examiner report

June 2025

The June 2025 papers put weight on bonding and structure, oxidation numbers and redox, ion and gas tests, making salts, petroleum and organic structures, and practical work on rates, energy changes, graphs and planning. The report points to poor recall of tests, indicator colours and solubility rules, and to answers about whole substances when the question was about particles. Better scripts quoted syllabus definitions exactly, put a sign on every oxidation number, described what was really seen and tied rate to collision frequency. Weaker scripts left conditions unqualified, swapped look-alike names such as ethane and ethene, stopped calculations at a fraction and ruled straight lines through curved data.

Where marks were lost

• Papers 41–43: oxidation numbers written without a sign, and questions asking for an explanation using oxidation numbers answered another way. Halogen displacement ionic equations kept the spectator ions.
• Papers 41–43: a covalent bond described as more than one shared pair; “free” written for mobile electrons; alcohol names with no position number; esters drawn as acids.
• Papers 31–33: wrong reagent or precipitate colour in the halide test; the hydrogen test given only as a “pop test”; cracking confused with fractional distillation.
• Papers 21–23: a 1 : 1 ratio assumed, or percentages divided instead of moles; a product chosen as the oxidising or reducing agent.
• Papers 51–53 and 61–63: straight lines through curved points, lines in pen, missing units; claims that repeats make results more reliable or accurate; “gas given off” instead of fizzing.

Grade thresholds – June 2025

Option	Components	Max	A*	A	B	C	D	E	F	G
BX	21, 41, 51	200	171	143	115	88	76	65	53	41
BY	22, 42, 52	200	172	145	116	88	77	66	54	42
BZ	23, 43, 53	200	173	146	117	88	75	63	52	41
CX	21, 41, 61	200	172	145	116	88	76	65	54	43
CY	22, 42, 62	200	173	146	117	89	78	67	55	43
CZ	23, 43, 63	200	173	147	118	89	77	66	55	44
FX	11, 31, 51	200	–	–	–	106	88	71	53	35
FY	12, 32, 52	200	–	–	–	109	93	78	61	44
FZ	13, 33, 53	200	–	–	–	110	92	74	56	38
GX	11, 31, 61	200	–	–	–	106	88	71	54	37
GY	12, 32, 62	200	–	–	–	110	94	79	62	45
GZ	13, 33, 63	200	–	–	–	111	94	77	59	41

Official documents: past papers, mark schemes and examiner report

March 2025

March 2025 leaned on electrolysis, energetics, ion and gas tests, the particle model, iron extraction, organic structures and naming, and practical work on temperature change, qualitative analysis and planning. The multiple-choice reports warn that candidates picked options that were only partly correct, or true but not an answer to the question, and the Paper 12 report says expected observations were often not recalled. Better scripts used exact terms such as carbon–carbon double bond and frequency of collisions, drew electrons in pairs and checked against the Periodic Table. Weaker scripts mixed up how particles are arranged, spaced and moving, gave vague uses and definitions, and misremembered tests, conditions and solubility rules.

Where marks were lost

• Paper 42: half-equations with electrons on the wrong side, single atoms instead of diatomic molecules, or spectator ions left in. Bond energies subtracted where they should have been added.
• Paper 42: “fewer collisions” instead of a lower collision frequency; temperature said to change the activation energy; alkene names without the double-bond position.
• Paper 32: an incomplete hydrogen test; the halide test done with an acid that itself contains halide ions; “double bond” alone for unsaturation.
• Paper 12: the electron configuration of the atom given for an ion; mole ratios misused so answers came out two or four times too big.
• Papers 52 and 62: the more exothermic reaction judged by the highest temperature instead of the temperature change; an electroplating plan with the object on the wrong electrode, no power supply, or no washing, drying and weighing.

Grade thresholds – March 2025

Option	Components	Max	A*	A	B	C	D	E	F	G
BY	22, 42, 52	200	176	153	125	98	85	73	59	45
CY	22, 42, 62	200	177	154	126	99	85	72	58	44
FY	12, 32, 52	200	–	–	–	113	97	82	65	48
GY	12, 32, 62	200	–	–	–	114	97	81	64	47

Official documents: past papers, mark schemes and examiner report

November 2024

November 2024 covered bonding and physical properties, formulae and equations, electrolysis, redox and oxidation numbers, acids, salts and indicators, water treatment and purity, organic chemistry, and practical skills including graphs, titration and ion tests. Content newer to the syllabus, such as solubility rules and flame tests, was weak. Better scripts gave exact definitions, real observations, true comparisons and full working. Weaker scripts swapped paired terms such as endothermic and exothermic or saturated and unsaturated, confused the spacing of particles with ways of separating mixtures, and missed questions answered on diagrams.

Where marks were lost

• Papers 41–43: conduction put down to electrons, or to free rather than mobile ions; oxidation numbers written as charges, as Roman numerals or without a sign.
• Papers 41–43: product names given instead of what is seen; condensation polymers missing continuation bonds or with hydrogen forming two bonds; activation energy defined only in part.
• Papers 31–33: flame colours and gas tests not known; chlorine confused with chloride; near-miss definitions of hydrocarbon (leaving out “only”), alloy and homologous series.
• Papers 21–23: a catalyst said to raise yield or shift equilibrium; acid strength linked to concentration; anode and cathode swapped; the role of cryolite not known.
• Papers 61–63: volumetric and dropping pipettes confused; an anomalous point not treated as anomalous; an ion listed despite a negative test.

Grade thresholds – November 2024

Option	Components	Max	A*	A	B	C	D	E	F	G
BY	22, 42, 52	200	156	131	106	82	70	58	47	36
BZ	23, 43, 53	200	155	131	107	83	72	61	51	41
CX	21, 41, 61	200	158	133	108	84	71	59	47	35
CY	22, 42, 62	200	158	133	108	84	71	59	47	35
CZ	23, 43, 63	200	157	133	109	85	73	61	50	39
FY	12, 32, 52	200	–	–	–	107	91	76	62	48
FZ	13, 33, 53	200	–	–	–	107	92	77	64	51
GX	11, 31, 61	200	–	–	–	109	94	79	63	47
GY	12, 32, 62	200	–	–	–	109	93	77	62	47
GZ	13, 33, 63	200	–	–	–	109	93	77	63	49

Official documents: past papers, mark schemes and examiner report

June 2024

The Paper 42 report judged June 2024 stronger than June 2023, with fewer candidates caught out by newer syllabus content. The same weak spots still came back: ion and gas tests (the qualitative analysis notes are printed only on Papers 5 and 6), solubility rules, electrolysis products, air pollutants and how to reduce them, bonding explanations, oxidation numbers and organic naming. Better scripts read every qualifying word, answered by comparison, called charge carriers mobile rather than free, and wrote correct formulae. Weaker scripts repeated the stem, confused rate with time, gave formulae when names were wanted and skipped items with no answer line.

Where marks were lost

• Papers 31–33: chloride and sulfate tests rarely known, with observations guessed; the effects of sulfur dioxide and ways to cut it not known.
• Paper 41: covalent bonds said to be weak; intermolecular forces placed between atoms; precipitation ionic equations unbalanced or without state symbols.
• Paper 42: the mass of one mole of atoms not recognised; a vague energy change instead of enthalpy change; a second answer contradicting a correct first one.
• Paper 43: an aqueous anode half-equation written as if for a molten oxide; a darker equilibrium colour explained by a shift instead of particles per unit volume; names without locants.
• Papers 51 and 61: straight lines through curved data; truncating instead of rounding; a digital thermometer assumed to be more accurate.

Grade thresholds – June 2024

Option	Components	Max	A*	A	B	C	D	E	F	G
BX	21, 41, 51	200	164	135	106	78	67	57	46	35
BY	22, 42, 52	200	166	137	108	79	67	56	45	34
BZ	23, 43, 53	200	160	132	104	76	67	58	47	36
CX	21, 41, 61	200	167	137	107	78	67	57	47	37
CY	22, 42, 62	200	170	141	110	79	68	58	48	38
CZ	23, 43, 63	200	163	134	105	76	67	58	48	38
FX	11, 31, 51	200	–	–	–	106	89	72	55	38
FY	12, 32, 52	200	–	–	–	102	85	69	53	37
GX	11, 31, 61	200	–	–	–	106	89	72	56	40
GY	12, 32, 62	200	–	–	–	102	86	71	56	41
GZ	13, 33, 63	200	–	–	–	106	89	72	56	40

Official documents: past papers, mark schemes and examiner report

March 2024

March 2024 drew on bonding and the properties of ionic, covalent and metallic substances, redox, electrolysis and extraction, acids and salts including the solubility rules, halogens, equilibrium, organic naming and structures, and practical titration and planning. The report says some candidates did not know content first added to the syllabus for 2023 exams. Better scripts gave exact syllabus definitions, used the data supplied, showed working and wrote precise observations. Weaker scripts mixed up paired terms (soluble and insoluble, halogen and halide, filtrate and residue), gave vague or one-sided answers, and answered a different question from the one set.

Where marks were lost

• Paper 42: the covalent bond definition, which needs exactly one shared pair between two atoms, was the hardest item on the paper. Candidates also used s, p, d notation, which is beyond the syllabus.
• Paper 42: solubility rules not known; full equations written where ionic precipitation equations were wanted; the equilibrium arrow left off for a weak acid.
• Paper 32: a precipitate described when a flame colour was needed; unsaturated defined as for solutions; what cracking is given instead of why it is done.
• Paper 22: statements chosen that were only partly true, such as the right process at the wrong electrode; an energy calculation not scaled for two moles.
• Papers 52 and 62: the wrong pair of experiments compared, a ratio inverted or rounded twice; heating said to change the titre through rate; catalysts said to take no part in a reaction.

Grade thresholds – March 2024

Option	Components	Max	A*	A	B	C	D	E	F	G
BY	22, 42, 52	200	162	135	108	81	69	57	46	35
CY	22, 42, 62	200	164	136	108	81	69	57	46	35
FY	12, 32, 52	200	–	–	–	106	92	78	64	50
GY	12, 32, 62	200	–	–	–	106	92	78	64	50

Official documents: past papers, mark schemes and examiner report

November 2023

Several November 2023 reports say terms added in the 2023 syllabus were poorly known, including enthalpy change, activation energy, how the greenhouse effect works and catalytic converters. Oxidation numbers caused trouble widely. Chemical tests, electrolysis products, petroleum fractions, organic reactions and structures, and the endothermic/exothermic split were weak across the series. Better scripts answered the exact question, compared rates with comparative words, gave colour and state in observations and wrote correct formulae. Weaker scripts repeated the stem, rearranged reactant names to make up products, confused rate with time, and left diagram and graph items blank because no answer line was printed.

Where marks were lost

• Papers 31–33: the order, uses and property trends of petroleum fractions, often left blank; sulfate, nitrate, sulfur dioxide and unsaturation tests rarely recalled.
• Paper 41: the Avogadro constant misused; halogen displacement written with full formulae; greenhouse gases linked to the ozone layer.
• Paper 42: oxidation numbers without a sign; filtrate and residue confused; a precipitate heated to the crystallisation point; energy-profile arrows at the wrong levels or double-headed.
• Paper 43: metallic bonding described as ionic, or electrons called free; the roles of coke and limestone in iron extraction.
• Papers 52, 53, 61, 62: awkward scales and points at wrong x-values; mixed decimal places; thermometers not read to half a division; flame tests with the sample near the flame (Paper 61).

Grade thresholds – November 2023

Option	Components	Max	A*	A	B	C	D	E	F	G
BY	22, 42, 52	200	148	125	102	79	68	57	46	35
BZ	23, 43, 53	200	154	131	108	86	75	65	55	45
CX	21, 41, 61	200	153	128	103	79	67	56	45	34
CY	22, 42, 62	200	149	126	103	80	69	58	46	34
CZ	23, 43, 63	200	156	133	110	88	76	65	54	43
FY	12, 32, 52	200	–	–	–	107	92	77	63	49
FZ	13, 33, 53	200	–	–	–	106	91	77	64	51
GX	11, 31, 61	200	–	–	–	107	92	77	63	49
GY	12, 32, 62	200	–	–	–	108	93	78	63	48
GZ	13, 33, 63	200	–	–	–	108	92	77	63	49

Official documents: past papers, mark schemes and examiner report

June 2023

June 2023 was the first June series on the updated syllabus. The report says newer content was often unfamiliar: thymolphthalein, halogen colours, where the raw materials for the Contact and Haber processes come from, and photochemical substitution of alkanes. The Core multiple-choice papers were found hard, the Extended ones mostly accessible. Ion and gas tests, environmental chemistry, electrolysis of aqueous solutions and definitions were weak throughout. Better scripts gave exact definitions and explained rate using particles and collision frequency. Weaker scripts mixed up rate and time, wrote an equation when a formula was wanted, and gave several answers that contradicted each other.

Where marks were lost

• Papers 31–33: cation, halide, chlorine, flame and bromine-water tests misremembered, and the word “precipitate” left out; isotopes not described as atoms.
• Paper 41: a catalyst “not used up” instead of unchanged; cryolite called a catalyst rather than a solvent; the filtrate crystallised instead of the residue being washed and dried.
• Paper 42: concentrations at equilibrium called equal instead of constant, with forward and reverse rates not mentioned; a one-way arrow for a weak acid; pressures in kPa.
• Paper 43: high melting point explained without a giant covalent structure; electrons on the wrong side of half-equations.
• Papers 51 and 61: burette readings such as 21 instead of 21.0; readings added; titre ratios inverted; volumetric and dropping pipettes confused.

Grade thresholds – June 2023

Option	Components	Max	A*	A	B	C	D	E	F	G
BX	21, 41, 51	200	158	129	100	71	61	51	41	31
BY	22, 42, 52	200	154	125	96	67	58	49	41	33
BZ	23, 43, 53	200	155	126	97	68	58	48	40	32
CX	21, 41, 61	200	161	131	101	72	61	51	42	33
CY	22, 42, 62	200	157	128	99	70	61	52	44	36
CZ	23, 43, 63	200	159	129	99	70	60	51	43	35
FX	11, 31, 51	200	–	–	–	95	79	63	47	31
FY	12, 32, 52	200	–	–	–	98	81	65	50	35
GX	11, 31, 61	200	–	–	–	96	79	63	48	33
GY	12, 32, 62	200	–	–	–	101	84	68	53	38
GZ	13, 33, 63	200	–	–	–	101	84	68	52	36
P1	50	90	84	78	60	43	36	29	21	13

Official documents: past papers, mark schemes and examiner report

March 2023

March 2023 was the first series on the revised syllabus, and the report says new content caught candidates out: cooling curves, the meaning and sign of an enthalpy change, the raw materials for the Haber process, flue gas desulfurisation, water of crystallisation, Roman-numeral oxidation numbers and the volumetric pipette. Older topics caused trouble too, in particular how metals react with water, steam and dilute acid, the blast furnace, and making dry crystals. Better scripts were precise, used the diagram or data given and followed the instructions. Weaker scripts used everyday wording, recited definitions instead of applying them, and missed key words in the question.

Where marks were lost

• Paper 12: reactions of metals with cold water, steam or dilute acid not known, so the reactivity order was guessed; protons said to move instead of electrons; hydrated confused with anhydrous.
• Paper 22: on cooling curves, forgetting that temperature holds steady during a change of state; the substance reduced named instead of the reducing agent.
• Paper 32: filter paper misplaced and residue and filtrate swapped; solutions heated to dryness instead of to the crystallisation point; blast furnace stages confused.
• Paper 42: the enthalpy change and its negative sign not explained; “more collisions” without frequency; oxidation numbers without a sign, or called valency.
• Papers 52 and 62: inconsistent decimal places; “cloudy” for a precipitate; acid concentration and temperature not controlled in a plan.

Grade thresholds – March 2023

Option	Components	Max	A*	A	B	C	D	E	F	G
BY	22, 42, 52	200	158	135	112	89	74	60	47	34
CY	22, 42, 62	200	157	135	113	91	76	62	49	36
FY	12, 32, 52	200	–	–	–	108	92	77	61	45
GY	12, 32, 62	200	–	–	–	110	94	79	63	47

Official documents: past papers, mark schemes and examiner report

November 2022

November 2022 drew heavily on organic chemistry, structure and bonding, metal extraction, salt preparation, equilibrium and rates, and ion and gas tests. The multiple-choice reports single out organic chemistry, structure and bonding, calculations and reactions that give off gases as weak. On the theory papers, better scripts used exact definitions, wrote correct ionic equations, explained rate and equilibrium changes in full and described real observations. Weaker scripts confused time with rate, named products when asked what is seen, ignored qualifying words in the question, drew atoms with impossible numbers of bonds and gave vague uses or effects. The practical reports stress consistent readings, clean graph lines and plans with quantities.

Where marks were lost

• Papers 41–43: full symbol equations written instead of ionic ones; electrons on the wrong side of half-equations; equilibrium described as the reaction shifting, or concentrations becoming equal.
• Papers 41–43: rate changes explained without collision frequency and the share of collisions with enough energy; metallic bonding described as ionic.
• Papers 31–33: vague definitions of cracking, thermal decomposition, incomplete combustion, alloy and homologous series; time taken treated as rate; energy from fuels not divided by the mass burned.
• Papers 21–23: the mole ratio or limiting reactant ignored; the catalyst placed at the wrong stage of the Contact process.
• Papers 52 and 62: changes worked out from the previous reading instead of the start; raw values plotted instead of changes. Paper 61: heating to constant mass not known.

Grade thresholds – November 2022

Option	Components	Max	A*	A	B	C	D	E	F	G
BX	21, 41, 51	200	150	127	104	82	70	59	48	37
BY	22, 42, 52	200	150	127	104	82	70	59	48	37
BZ	23, 43, 53	200	152	130	108	86	74	62	50	38
CX	21, 41, 61	200	149	127	105	83	71	59	47	35
CY	22, 42, 62	200	151	128	105	82	70	58	46	34
CZ	23, 43, 63	200	153	131	109	88	75	62	49	36
FY	12, 32, 52	200	–	–	–	108	93	78	64	50
FZ	13, 33, 53	200	–	–	–	108	93	79	64	49
GX	11, 31, 61	200	–	–	–	104	90	76	62	48
GY	12, 32, 62	200	–	–	–	108	92	77	62	47
GZ	13, 33, 63	200	–	–	–	110	94	79	63	47
P1	50	90	72	63	54	45	36	27	18	9

Official documents: past papers, mark schemes and examiner report

June 2022

The Core multiple-choice papers were found hard in June 2022, which the report links partly to disruption from the pandemic; the Extended ones were more accessible. Recall let many candidates down: ion and gas tests, uses of named substances such as petroleum fractions and lime, NPK fertilisers, and which metals are extracted with carbon rather than by electrolysis. Better scripts were precise, made real comparisons and followed the question. Weaker scripts mixed up the charge and mass of subatomic particles, muddled particle arrangement, spacing and motion, wrote “free” for mobile electrons or ions, and listed products when observations were asked for. The practical papers again suggested limited lab experience.

Where marks were lost

• Paper 41: metallic bonding without positive ions, delocalised electrons and the attraction between them; features of dynamic equilibrium.
• Paper 42: how to make a saturated solution, and what saturated means; ionic bonding diagrams that did not show electron transfer.
• Paper 43: the syllabus definition of a base; a catalyst said to take no part in the reaction; mole ratios rounded too early in an empirical formula.
• Papers 31–33: relative mass read as relative charge; hydrogen given as a product of acids with oxides or carbonates; the halide test; how fractional distillation separates fractions.
• Papers 51 and 61: unlabelled lines and missing units; more readings said to improve accuracy. Papers 53 and 63: why a white tile is used; heating said to change a titre.

Grade thresholds – June 2022

Option	Components	Max	A*	A	B	C	D	E	F	G
BX	21, 41, 51	200	157	129	101	73	62	52	42	32
BY	22, 42, 52	200	141	115	89	64	55	46	37	28
BZ	23, 43, 53	200	147	120	93	67	57	48	39	30
CX	21, 41, 61	200	159	130	101	72	61	51	41	31
CY	22, 42, 62	200	145	118	91	65	55	46	37	28
CZ	23, 43, 63	200	146	119	92	65	55	46	37	28
FX	11, 31, 51	200	–	–	–	107	90	73	56	39
FY	12, 32, 52	200	–	–	–	103	86	69	53	37
FZ	13, 33, 53	200	–	–	–	104	87	71	56	41
GX	11, 31, 61	200	–	–	–	106	89	72	55	38
GY	12, 32, 62	200	–	–	–	104	86	69	53	37
GZ	13, 33, 63	200	–	–	–	102	85	69	54	39
P1	50	90	72	63	54	45	36	27	18	9

Official documents: past papers, mark schemes and examiner report

March 2022

March 2022 leaned on atomic structure and bonding diagrams, the reactivity series, energetics, electrolysis, organic chemistry (cracking, esters, condensation polymers) and practical skills such as making salts, ion tests and graphs. On both multiple-choice papers candidates swapped endothermic and exothermic and misremembered the reactivity order. Better scripts gave exact definitions, drew diagrams with the right electron counts and bonds, read every key word and showed working. Weaker scripts gave everyday answers, described products instead of observations, and wrote general statements instead of using the information given.

Where marks were lost

• Paper 42: a slowing rate not linked to falling concentration and collision frequency; ions called free; conduction in an electrolyte put down to electrons.
• Paper 42: bond making assumed to release less energy than bond breaking uses in an exothermic change; bonds left out of the totals; carbon with three bonds and missing O–H bonds.
• Paper 32: alloy defined without the idea of a mixture; thermal decomposition explained using only one of its two words; solutions heated to dryness when crystallising.
• Paper 22: weak acids not recalled as partly dissociated; ion movement right but electron movement wrong in electrolysis.
• Papers 52 and 62: readings not to a consistent resolution; dot-to-dot lines; dropwise and excess observations not given separately; more water thought to give a bigger temperature rise.

Grade thresholds – March 2022

Option	Components	Max	A*	A	B	C	D	E	F	G
BY	22, 42, 52	200	142	118	94	70	58	46	35	24
CY	22, 42, 62	200	143	119	95	71	58	46	35	24
FY	12, 32, 52	200	–	–	–	102	84	67	48	29
GY	12, 32, 62	200	–	–	–	103	85	67	48	29

Official documents: past papers, mark schemes and examiner report

November 2021

In November 2021, recall of core facts decided many marks. Ion and gas tests, colours of compounds, redox vocabulary, equilibrium shifts and basic organic chemistry (homologous series, structures, combustion products, polymers) were weak on every type of paper. Better scripts read the question closely, used exact chemical terms and answered at the level of particles, not whole substances. Weaker scripts repeated words from the question, gave chemical properties when physical ones were asked for, and were vague about pollution and uses. Ionic equations and half-equations remained a weakness at Extended level, and the practical papers pointed to limited hands-on experience, especially in analysis and planning.

Where marks were lost

• Papers 31–33: tests for halide, sulfate, nitrate, iron(III) and zinc ions rarely known; “-ine” written where “-ide” was meant; vague definitions of thermal decomposition, alloy, polymer and cracking.
• Paper 41: precipitation and electrode ionic equations; dynamic equilibrium described loosely, with no direction of shift.
• Paper 42: bond breaking and bond making both described as releasing energy; energy profiles without the activation energy hump; an “endothermic side” of an equilibrium.
• Papers 21–23: “reduction” confused with “reducing agent”; a 1 : 1 ratio used instead of the equation’s ratio; the bold word “not” missed.
• Papers 52 and 62: burette readings as whole numbers; not knowing why the burette is rinsed with the solution it will hold; a salt made when the plan asked for a metal from its ore.

Grade thresholds – November 2021

Option	Components	Max	A*	A	B	C	D	E	F	G
BX	21, 41, 51	200	136	114	92	71	62	53	43	33
BY	22, 42, 52	200	138	116	94	73	62	51	42	33
BZ	23, 43, 53	200	142	120	98	77	66	55	46	37
CX	21, 41, 61	200	136	114	92	70	61	52	43	34
CY	22, 42, 62	200	138	116	94	72	61	50	41	32
CZ	23, 43, 63	200	142	120	98	76	65	55	46	37
FY	12, 32, 52	200	–	–	–	107	93	80	66	52
FZ	13, 33, 53	200	–	–	–	106	91	77	62	47
GX	11, 31, 61	200	–	–	–	104	90	77	65	53
GY	12, 32, 62	200	–	–	–	106	92	79	65	51
GZ	13, 33, 63	200	–	–	–	105	91	77	62	47

Official documents: past papers, mark schemes and examiner report

June 2021

Electrolysis appeared at every level in June 2021. Candidates had to tell molten from aqueous electrolytes and name the element formed, not the ion. The reactivity series, ion and gas tests, and identifying a substance from chemical evidence also came up often. The reports say standard definitions split strong from weak scripts: hydrocarbon, alloy, electrolysis, equilibrium, incomplete combustion and covalent bond. Weak versions often left out a key word. At Extended level, the wording of equilibrium shifts, organic structures with correct bonding and mole work on water of crystallisation separated scripts. The practical reports suggest less hands-on experience than usual.

Where marks were lost

• Paper 11: sodium predicted at the cathode in aqueous electrolysis; an atom left out of a formula-mass sum; carbon with too many bonds in a polymer.
• Papers 31–33: definitions missing key words, including covalent bond without “pair”; tests for lithium, calcium, chloride, water, unsaturation and oxygen; parts left blank on Paper 33.
• Paper 41: equilibrium shifts worded as “more product” instead of left or right; concentrations said to become equal; mole ratios rounded wrongly in empirical formulae.
• Paper 42: a name given when a formula was asked for; spectator ions left in equations; condensation-polymer linkages.
• Papers 51–53 and 61–63: mixed decimal places; a flame test confused with a splint test; “gas given off” as an observation; best-fit curves that wander from point to point.

Grade thresholds – June 2021

Option	Components	Max	A*	A	B	C	D	E	F	G
BX	21, 41, 51	200	141	116	91	67	56	46	37	28
BY	22, 42, 52	200	143	116	89	63	53	44	36	28
BZ	23, 43, 53	200	140	114	88	63	54	46	39	32
CX	21, 41, 61	200	142	117	92	67	57	47	38	29
CY	22, 42, 62	200	145	118	91	64	54	44	36	28
CZ	23, 43, 63	200	141	115	89	64	56	48	41	34
FX	11, 31, 51	200	–	–	–	92	76	61	46	31
FY	12, 32, 52	200	–	–	–	94	79	65	49	33
GX	11, 31, 61	200	–	–	–	92	77	62	47	32
GY	12, 32, 62	200	–	–	–	95	80	65	49	33
GZ	13, 33, 63	200	–	–	–	93	78	63	48	33

Official documents: past papers, mark schemes and examiner report

March 2021

March 2021 leaned on recall of definitions and standard facts: electrolysis products, the reactivity series, qualitative tests and colours, and the particle model. Examiners split scripts on exact wording, and the Paper 32 report adds that key words in the question, such as “negative”, “other” and “acidified”, were often missed. Weaker scripts were vague, confused mixtures with compounds, and described products instead of observations. Stronger Extended scripts explained equilibrium shifts and collision theory in full. On the practical papers, recording data to a consistent resolution and knowing why experiments are repeated made the difference.

Where marks were lost

• Paper 42: rates explained without collisions per unit time or the larger share of collisions above the activation energy; equilibrium shifts with no direction; condition ranges instead of single values with units.
• Paper 42: structures with wrong bonds or a missing O–H bond; converting mol/dm³ into g/dm³.
• Paper 32: names given when formulae were asked for; separation, arrangement and motion of particles mixed up; “a gas is formed” instead of an observation.
• Paper 12: electrolysis products of concentrated aqueous sodium chloride; colours of hydrated and anhydrous salts, with signs of guessing.
• Papers 52 and 62: burette values not all to one decimal place; “clear” used for colourless; repeats said to make results more accurate; a fume cupboard not chosen for a toxic gas.

Grade thresholds – March 2021

Option	Components	Max	A*	A	B	C	D	E	F	G
BY	22, 42, 52	200	141	118	95	72	62	52	42	32
CY	22, 42, 62	200	143	119	95	72	62	52	42	32
FY	12, 32, 52	200	–	–	–	96	79	62	45	28
GY	12, 32, 62	200	–	–	–	96	79	62	45	28

Official documents: past papers, mark schemes and examiner report

November 2020

Organic chemistry was the weakest area across the whole of November 2020, from multiple choice to Extended theory. Isomerism, addition reactions, fermentation, the hydration of ethene, esters and displayed formulae with correct bonding all caused trouble. The report marks candidates down again and again for loose definitions of element, isotope, electrolysis, equilibrium, saturated solution and homologous series. Salt preparation methods were often out of order or incomplete. Better scripts took data accurately from tables and graphs and kept observations apart from conclusions. Weaker scripts repeated the question, called effects “harmful”, mixed up rate with equilibrium, and confused reliability with accuracy in practical work.

Where marks were lost

• Papers 11–13 and 21–23: yeast said to be what is fermented; dehydrating a hydrated salt treated as exothermic; J mixed with kJ and cm³ with dm³.
• Papers 31–33: displayed formulae, the bromine water test and fermentation conditions; salt preparation steps out of order; electrodes drawn out of the liquid.
• Paper 41: a barrier method described when sacrificial protection was asked for; alloy hardness explained without different-sized atoms.
• Papers 42 and 43: word equations where symbol equations were needed; rate confused with equilibrium; “similar” used for “same” when defining isomers.
• Papers 51–53 and 61–63: burette readings not to one decimal place (0 instead of 0.0); the indicator colour given instead of the colour change; residue confused with filtrate.

Grade thresholds – November 2020

Option	Components	Max	A*	A	B	C	D	E	F	G
BX	21, 41, 51	200	153	130	107	84	70	57	44	31
BY	22, 42, 52	200	138	116	94	72	61	51	40	29
BZ	23, 43, 53	200	152	131	110	89	76	63	50	37
CX	21, 41, 61	200	154	130	106	83	69	56	43	30
CY	22, 42, 62	200	140	118	96	74	62	51	40	29
CZ	23, 43, 63	200	152	131	110	89	76	63	50	37
FY	12, 32, 52	200	–	–	–	108	92	76	60	44
FZ	13, 33, 53	200	–	–	–	106	90	74	58	42
GX	11, 31, 61	200	–	–	–	106	90	74	58	42
GY	12, 32, 62	200	–	–	–	110	93	76	60	44
GZ	13, 33, 63	200	–	–	–	106	90	74	58	42

Official documents: past papers, mark schemes and examiner report

March 2020

March 2020 leaned on metal extraction (the blast furnace and aluminium electrolysis), rates followed by collecting a gas, simple organic chemistry (fermentation, the unsaturation test, polymers) and ion and gas tests. The report treats precision as the dividing line. Better scripts used exact terms, named a specific substance instead of a general “salt”, made real comparisons and described real practical steps. Weaker scripts were vague or contradicted themselves, and mixed up similar processes such as fermentation and the hydration of ethene, or the blast furnace and steelmaking. They also drew organic structures with the wrong number of bonds, struggled with ionic and half-equations, and wrote theory where a method was needed.

Where marks were lost

• Paper 32: the roles of limestone and burning coke in the blast furnace; ethene hydration conditions given for fermentation; rate theory written when a practical method was asked for.
• Paper 42: formulae or symbol equations given where names or word equations were asked for; anode half-equations and precipitation ionic equations; concentrations at equilibrium called “the same”.
• Paper 12: electrons, not ions, said to carry charge through the electrolyte; dissolved substances thought to be removed in water treatment.
• Paper 52: awkward scales and straight lines through curved data; averaging said to remove a systematic error; “clear” for colourless.
• Paper 62: the direction of water flow through a condenser; lab and industrial fractional distillation confused; a positive result written for an absent ion.

Grade thresholds – March 2020

Option	Components	Max	A*	A	B	C	D	E	F	G
BY	22, 42, 52	200	169	146	123	100	84	69	55	41
CY	22, 42, 62	200	170	147	124	101	86	71	57	43
FY	12, 32, 52	200	–	–	–	125	107	89	70	51
GY	12, 32, 62	200	–	–	–	126	108	91	72	53

Official documents: past papers, mark schemes and examiner report

How to use this page

1. Pick a series and sit the paper for your tier under timed conditions: Papers 1 or 2, 3 or 4, and 5 or 6. Check the exam calendar to plan how many papers you can fit in before your exams.
2. Mark it strictly with the official mark scheme. Look up any command word you misread on our command words page.
3. Read the notes for that series on this page, then the full examiner report. Write down every mark you lost for a reason listed there.
4. Find each weak topic on the IGCSE Chemistry checklist and fix it with the notes and practice on the IGCSE Chemistry hub.
5. Re-test yourself. Use the free Core diagnostic or Extended diagnostic (all subjects are on the diagnostics page), and the 0620 self-check question bank.
6. Compare your raw mark with the thresholds for that series only as a rough guide. For June 2026 thresholds for our main syllabuses, see grade thresholds.
7. If you want a teacher to go through your papers with you, book a free trial lesson.

About these notes

The grade thresholds are copied from Cambridge’s grade-threshold documents, and the examiner notes are our own summaries of Cambridge’s Principal Examiner Reports for Teachers for the series listed above, written in our words. Thresholds change every series and must never be used to predict future ones. If you spot a mistake, please report a correction.