AQA GCSE Chemistry: the mark scheme language that gets the mark
237 wording rules from real AQA mark schemes and examiner reports, 2018–2025 · organised by topic
GCSE marks live and die on exact wording. AQA mark schemes spell it out: (allow …) lists the alternatives that still score, do not accept … names the answers that score nothing, and where a specific word is required, only that word earns the mark. Examiner reports say the same thing after every exam — what students had to say, and which popular phrasings were "insufficient". Everything below is taken from real AQA GCSE Chemistry mark schemes Mark scheme and real examiner reports Examiner report — nothing invented.
Quiz mode: the wording is hidden — read the source line, say the answer out loud, then tap the card to check.
4.1 Atomic structure and the periodic table35
Mark schemeCoefficient of CO = 3 (allow multiples)AQA GCSE Chemistry Paper 1, Foundation, 2023 · spec 4.1.1.1
Mark schemeCoefficient of Fe = 2 (allow multiples)AQA GCSE Chemistry Paper 1, Foundation, 2023 · spec 4.1.1.1
Mark schemeEquation correctly balanced: C4H9OH + 6O2 -> 4CO2 + 5H2O (allow correct multiples)AQA GCSE Chemistry Paper 2, Higher, 2021 · spec 4.1.1.1
Mark schemeModel A has positive charge spread throughout the atom (allow is a ball of positive charge)AQA GCSE Chemistry Paper 1, Foundation, 2024 · spec 4.1.1.3
Mark schemeModel A: plum pudding (model) (allow Thomson model)AQA GCSE Chemistry Paper 1, Foundation, 2024 · spec 4.1.1.3
Mark schemeModel A: plum pudding (model), allow Thomson modelAQA GCSE Chemistry Paper 1, Foundation, 2024 · spec 4.1.1.3
Mark schemeModel B: Bohr (model) (allow nuclear model, planetary model, Rutherford-Bohr model)AQA GCSE Chemistry Paper 1, Foundation, 2024 · spec 4.1.1.3
Mark schemeModel B: Bohr (model), allow nuclear model, planetary model, Rutherford-Bohr modelAQA GCSE Chemistry Paper 1, Foundation, 2024 · spec 4.1.1.3
Mark schemeWith (negative) electrons embedded (do not accept references to protons/nuclei/neutrons)AQA GCSE Chemistry Paper 1, Foundation, 2023 · spec 4.1.1.3
Mark schemeAtoms with the same number of protons (allow atoms of the same element / same atomic number)AQA GCSE AQA past paper · spec 4.1.1.5
Mark schemeSame number of protons (allow electrons)AQA GCSE Chemistry Paper 1, Foundation, 2023 · spec 4.1.1.5
Mark schemeReason: tennessine is in Group 7 (allow same as group number, allow halogen)AQA GCSE Chemistry Paper 1, Foundation, 2023 · spec 4.1.2.1
Mark schemeArgon has a full outer shell (of electrons) (allow eight outer shell electrons)AQA GCSE Chemistry Paper 1, Foundation, 2025 · spec 4.1.2.4
Mark scheme(So) the outer electron in rubidium is more easily lost (allow less energy needed to remove it)AQA GCSE Chemistry Paper 1, Higher, 2022 · spec 4.1.2.5
Mark scheme(So) there is less (electrostatic) attraction between the nucleus and the outer electron in rubidium (allow more shielding)AQA GCSE Chemistry Paper 1, Higher, 2022 · spec 4.1.2.5
Mark schemeTungsten has a higher melting/boiling point than potassium (allow converse for potassium)AQA GCSE Chemistry Paper 1, Foundation, 2025 · spec 4.1.2.5
Mark schemeTungsten is harder than potassium (allow converse: potassium is softer / more malleable / more ductile)AQA GCSE Chemistry Paper 1, Foundation, 2025 · spec 4.1.2.5
Mark schemeTungsten is less reactive than potassium (allow converse: potassium is more reactive, or a specific reaction showing the difference)AQA GCSE Chemistry Paper 1, Foundation, 2025 · spec 4.1.2.5
Mark schemeThe intermolecular forces increase (allow become stronger)AQA GCSE Chemistry Paper 1, Foundation, 2020 · spec 4.1.2.6
Mark schemeGroup 1 elements are not useful as catalysts (allow converse: transition elements are used as catalysts)AQA GCSE Chemistry Paper 1, Higher, 2022 · spec 4.1.3.1
Mark schemeTungsten is stronger than potassium (allow converse for potassium)AQA GCSE Chemistry Paper 1, Foundation, 2025 · spec 4.1.3.1
Mark schemeGroup 1 elements are less strong / softer (allow converse; allow more malleable / ductile)AQA GCSE Chemistry Paper 1, Higher, 2022 · spec 4.1.3.2
Mark schemeGroup 1 elements have lower densities (allow converse for transition elements)AQA GCSE Chemistry Paper 1, Higher, 2022 · spec 4.1.3.2
Mark schemeGroup 1 elements have lower melting / boiling points (allow converse for transition elements)AQA GCSE Chemistry Paper 1, Higher, 2022 · spec 4.1.3.2
Mark schemeTungsten is denser than potassium (allow converse for potassium)AQA GCSE Chemistry Paper 1, Foundation, 2025 · spec 4.1.3.2
Mark schemeThen crystallise the (magnesium chloride) solution (allow evaporate the water)AQA GCSE Combined Science Chemistry Paper 1, Higher, 2023 · spec 5.1.1.2
Mark schemeStates 6 electrons (allow electron structure 2,4)AQA GCSE Combined Science Chemistry Paper 1, Foundation, 2021 · spec 5.1.1.4
Mark schemeFinal answer of 1837 (allow 1836.645076 or a value correctly rounded to at least 3 significant figures)AQA GCSE Combined Science Chemistry Paper 1, Higher, 2023 · spec 5.1.1.5
Mark schemeChlorine has fewer (electron) shells than bromine (allow chlorine is a smaller atom)AQA GCSE Combined Science Chemistry Paper 1, Higher, 2024 · spec 5.1.2.3
Mark schemeSo the outer shell (electrons) is closer to the nucleus (allow less shielding)AQA GCSE Combined Science Chemistry Paper 1, Higher, 2024 · spec 5.1.2.6
Examiner reportThere was no credit for balancing incorrect formulae.AQA GCSE Chemistry Paper 1, Higher, 2025 · spec 4.1.1.1
Examiner reportFor the first marking point, the idea of both the shape and the charge were needed.AQA GCSE Chemistry Paper 1, Higher, 2025 · spec 4.1.1.3
Examiner reportThis was insufficient as the question required students to answer in terms of electrons.AQA GCSE Chemistry Paper 1, Higher, 2023 · spec 4.1.2.4
Examiner reportMost students described a property of either a Group 1 element or a transition element without reference to the other; this did not gain credit as a comparison was needed.AQA GCSE Chemistry Paper 1, Foundation, 2022 · spec 4.1.3.1
Examiner reportA yellow flame was a common answer for those who gained one of the marks although ‘flame’ was insufficient.AQA GCSE Combined Science Chemistry Paper 1, Higher, 2023 · spec 5.1.2.5
4.2 Bonding, structure, and the properties of matter21
Mark schemeCalcium's outer shell / electrons are further from the nucleus (allow calcium has more shells)AQA GCSE AQA past paper · spec 4.2.1.2
Mark schemeTo form Ca2+ ions and Cl- ions (allow calcium ion(s) and chloride ion(s))AQA GCSE Chemistry Paper 1, Foundation, 2023 · spec 4.2.1.2
Mark scheme(Thermal) energy is transferred (allow heat is transferred)AQA GCSE AQA past paper · spec 4.2.1.5
Mark schemeColumn: condensation (allow gas to liquid)AQA GCSE Chemistry Paper 2, Foundation, 2025 · spec 4.2.2.1
Mark schemeSo the forces between molecules are weak (allow the intermolecular forces are weak)AQA GCSE Chemistry Paper 1, Higher, 2024 · spec 4.2.2.1
Mark schemeDifferent sizes (allow diameters; do not accept shapes)AQA GCSE Chemistry Paper 1, Foundation, 2023 · spec 4.2.2.7
Mark schemeSo the layers cannot easily slide (allow atoms cannot slide over each other)AQA GCSE AQA past paper · spec 4.2.2.7
Mark schemeThe alloy / mixture has different sized atoms (allow ions)AQA GCSE AQA past paper · spec 4.2.2.7
Mark schemeTo about 183 degrees Celsius (allow 182-184 C, or to about 62% tin)AQA GCSE Chemistry Paper 1, Foundation, 2023 · spec 4.2.2.7
Mark schemeGiant (covalent) structure (allow macromolecular, allow giant lattice)AQA GCSE Chemistry Paper 1, Higher, 2022 · spec 4.2.3.1
Mark schemeMany covalent bonds must be brokenAQA GCSE Chemistry Paper 1, Higher, 2022 · spec 4.2.3.1
Mark schemeGraphite is inert (allow unreactive)AQA GCSE Chemistry Paper 1, Foundation, 2020 · spec 4.2.3.2
Mark schemeSurface area : volume ratio = 96 : 64 (allow correct use of an incorrectly determined volume)AQA GCSE Chemistry Paper 1, Foundation, 2025 · spec 4.2.4.1
Mark schemeIons are free to move (or allow charge to flow)AQA GCSE Combined Science Chemistry Paper 1, Higher, 2022 · spec 5.2.2.3
Mark schemeDelocalised electrons (allow free electrons)AQA GCSE Combined Science Chemistry Paper 1, Higher, 2022 · spec 5.2.2.8
Mark schemeSo the delocalised electrons carry electrical charge through the structure (allow move through the structure)AQA GCSE Combined Science Chemistry Paper 1, Higher, 2021 · spec 5.2.3.2
Examiner reportMost students did recognise that a lot of energy was needed to break bonds but had contradicted this marking point earlier in their response by referring to the bonds as intermolecular forces.AQA GCSE Chemistry Paper 1, Higher, 2025 · spec 4.2.1.3
Examiner reportThis question proved to be difficult, with few students giving fully correct answers to gain all 4 marks and with a third of students gaining no credit.AQA GCSE Chemistry Paper 1, Higher, 2023 · spec 4.2.2.4
Examiner reportTo enter Level 2 a comparison, reference to magnitude and reference to the structure and bonding of silicon dioxide or poly(ethene) were required.AQA GCSE Combined Science Chemistry Paper 1, Higher, 2025 · spec 5.2.2.6
Examiner reportAlthough 4.20 is correctly rounded to 3 significant figures it does not come from a calculation using all values in the question (ie 13.5% has not been used) so gains no credit.AQA GCSE Combined Science Chemistry Paper 1, Foundation, 2024 · spec 5.2.2.7
Examiner reportStudents were asked to give two conclusions, so statements that merely quoted numerical values and years from the graph or made predictions of the future were insufficient.AQA GCSE Combined Science Chemistry Paper 1, Foundation, 2024 · spec 5.2.2.7
4.3 Quantitative chemistry10
Mark schemeCorrect reactants and products for combustion of butanol (allow C4H9OH or C4H10O, plus O2, giving CO2 and H2O)AQA GCSE Chemistry Paper 2, Higher, 2021 · spec 4.3.1.1
Mark schemeFully correct balanced equation: 2Rb + 2H2O -> 2RbOH + H2 (allow multiples)AQA GCSE Chemistry Paper 1, Higher, 2022 · spec 4.3.1.1
Mark schemeSubstitution: (2 x 56) + (3 x 16), allow 112 + 48AQA GCSE Chemistry Paper 1, Foundation, 2023 · spec 4.3.1.2
Mark schemeA gas was produced (allow oxygen for gas)AQA GCSE Chemistry Paper 2, Higher, 2025 · spec 4.3.1.3
Mark schemePercentage atom economy = 77.9 (%) (allow 77.9141... correctly rounded to at least 2 sig figs)AQA GCSE Chemistry Paper 1, Foundation, 2023 · spec 4.3.3.2
Mark schemeMeasure volumes with a measuring cylinder (allow pipette / burette)AQA GCSE AQA past paper · spec 4.3.4
Examiner reportNo credit was given for stating the test for carbon dioxide.AQA GCSE Chemistry Paper 1, Foundation, 2018 · spec 4.3.1.3
Examiner reportCommon responses seen that were not credited included: • Hydrogen is flammable.AQA GCSE Chemistry Paper 1, Higher, 2019 · spec 4.3.2.3
Examiner reportThe majority of students calculated the number of moles of both aluminium and of iron oxide and then attempted with varying degrees of success to explain why the number of moles of aluminium was insufficient for the iron oxide. These students found it easier to express why there was insufficient aluminium or excess iron oxide.AQA GCSE Chemistry Paper 1, Higher, 2020 · spec 4.3.2.4
Examiner reportNo credit was given for multiplying a value by 24 unless that value was identified as a number of moles.AQA GCSE Chemistry Paper 1, Higher, 2020 · spec 4.3.5
4.4 Chemical changes36
Mark schemeAluminium is more reactive than carbon (allow "aluminium is above carbon in the reactivity series")AQA GCSE Chemistry Paper 1, Foundation, 2019 · spec 4.4.1.1
Mark schemeSo carbon cannot displace aluminium (allow "replace") — or carbon cannot reduce aluminium oxide (allow "cannot remove oxygen from aluminium oxide" / "will not react with aluminium oxide")AQA GCSE Chemistry Paper 1, Foundation, 2019 · spec 4.4.1.1
Mark schemeRubidium's outer shell / electron is further from the nucleus (allow the rubidium atom is larger / has more shells)AQA GCSE Chemistry Paper 1, Higher, 2022 · spec 4.4.1.2
Mark schemeSo positive ions are formed more easily (allow electrons more easily lost)AQA GCSE AQA past paper · spec 4.4.1.2
Mark schemeSo the outer electrons are less strongly attracted to the nucleus (allow more shielded)AQA GCSE AQA past paper · spec 4.4.1.2
Mark schemeThe (blue) solution / ions produced are copper (allow copper nitrate/compound is blue)AQA GCSE Chemistry Paper 1, Foundation, 2020 · spec 4.4.1.2
Mark schemeSilicon is less reactive than carbon (allow converse; allow silicon is below carbon in the reactivity series)AQA GCSE Chemistry Paper 1, Higher, 2022 · spec 4.4.1.3
Mark schemeHeat the solution until crystallisation point is reached (allow heat until crystals start to form / to reduce the volume / to evaporate some of the water)AQA GCSE Chemistry Paper 1, Higher, 2022 · spec 4.4.2.3
Mark schemeLeave the solution to cool / crystallise (if no other mark awarded, allow "heat the solution to dryness" for 1 mark)AQA GCSE Chemistry Paper 1, Higher, 2022 · spec 4.4.2.3
Mark schemeZinc hydroxide (allow Zn(OH)2)AQA GCSE Chemistry Paper 1, Foundation, 2023 · spec 4.4.2.3
Mark scheme(An acid which) is partially ionised (allow partially dissociated)AQA GCSE AQA past paper · spec 4.4.2.4
Mark scheme(From 0) to 20 cm3 the pH increases gradually (allow increase from pH 1 to pH 3)AQA GCSE Chemistry Paper 1, Foundation, 2020 · spec 4.4.2.4
Mark schemeIn aqueous solution (allow when dissolved in water)AQA GCSE AQA past paper · spec 4.4.2.4
Mark schemeThere are no ions that are free to move (allow no ions in solution / no ions free to carry the charge)AQA GCSE Chemistry Paper 1, Higher, 2022 · spec 4.4.2.4
Mark scheme(Because) 23.90 cm3 is an anomalous result (allow not concordant / too high a value / the first titration is a rough value)AQA GCSE Chemistry Paper 1, Higher, 2022 · spec 4.4.2.5
Mark schemeAdd an indicator (to the alkali) (allow named indicator; do not accept universal indicator)AQA GCSE Chemistry Paper 1, Higher, 2024 · spec 4.4.2.5
Mark schemeSo the concentration of hydrogen ions is lower (allow ethanoic acid is only partially ionised)AQA GCSE Chemistry Paper 2, Higher, 2025 · spec 4.4.2.5
Mark schemeThe mean of titration numbers 2 to 5 is calculated (allow identification by titration number or volume; allow mean of the concordant results / mean of the results within 0.10 cm3)AQA GCSE Chemistry Paper 1, Higher, 2022 · spec 4.4.2.5
Mark schemeThe rate of reaction using ethanoic acid is lower (allow converse for nitric acid)AQA GCSE Chemistry Paper 2, Higher, 2025 · spec 4.4.2.6
Mark schemeBecause Cu2+ (copper) ions move to the negative electrode (allow cathode)AQA GCSE AQA past paper · spec 4.4.3.1
Mark schemeCrO4 2- (chromate) ions move to the positive electrode (allow anode)AQA GCSE AQA past paper · spec 4.4.3.1
Mark schemeReason: the (positive) electrode attracts ions of the opposite charge (allow opposite charges attract)AQA GCSE Chemistry Paper 1, Foundation, 2020 · spec 4.4.3.1
Mark schemeDanger of the dam bursting (allow the lake could overflow)AQA GCSE Chemistry Paper 1, Foundation, 2020 · spec 4.4.3.3
Mark schemeGraphite conducts electricity (allow has delocalised/free electrons)AQA GCSE Chemistry Paper 1, Foundation, 2020 · spec 4.4.3.4
Mark schemeReason: hydrogen is not a metal (allow hydrogen is a gas/not a solid; products at both electrodes are gases; product at negative electrode is not potassium; potassium is more reactive than hydrogen)AQA GCSE Chemistry Paper 1, Foundation, 2020 · spec 4.4.3.4
Mark schemeThe pH decreases (allow pH is lower)AQA GCSE Combined Science Chemistry Paper 1, Higher, 2022 · spec 5.4.2.5
Mark schemeCorrect reactants: Al3+ and electrons combining to form Al (allow unbalanced Al3+ + e- -> Al)AQA GCSE Combined Science Chemistry Paper 1, Higher, 2024 · spec 5.4.3.3
Examiner reportA control variable was needed for full marks to be awarded, as well as how the results would show which metal was the more reactive. Of those students who did realise what was required, many spoiled their control variable by referring to the same ‘amount’ of a substance instead of volume, or concentration, or mass, as appropriate to the substance.AQA GCSE Chemistry Paper 1, Higher, 2021 · spec 4.4.1.2
Examiner reportApproaches that were not accepted included: • trying to react the metal with the other metals • measuring melting or boiling point • looking at the periodic table.AQA GCSE Chemistry Paper 1, Foundation, 2018 · spec 4.4.1.2
Examiner reportResponses were often vague; for example ‘high reactivity’ for sodium was insufficient for the mark, as high reactivity on its own does not explain what the problem is.AQA GCSE Chemistry Paper 1, Foundation, 2024 · spec 4.4.1.2
Examiner reportThis was not possible, as insufficient detail was provided to identify any of the four metals.AQA GCSE Chemistry Paper 1, Higher, 2023 · spec 4.4.1.2
Examiner reportDefinitions of oxidation and reduction in terms of gain and loss of oxygen were not appropriate here and were not credited.AQA GCSE Chemistry Paper 1, Higher, 2020 · spec 4.4.1.4
Examiner reportMany students did not realise that they had been given the correct apparatus, and merely had to say what they would do to use that apparatus accurately.AQA GCSE Chemistry Paper 1, Foundation, 2024 · spec 4.4.2.5
Examiner reportStudents needed to give the idea of movement of the relevant ions to the positive electrode and to give a reason for that movement in terms of the attraction of opposite charges.AQA GCSE Chemistry Paper 1, Higher, 2020 · spec 4.4.3.1
Examiner reportCommon responses seen that were not credited included: • to melt the aluminium oxide so that it conducts electricity • so that the ions can move freely • to reduce costs.AQA GCSE Chemistry Paper 1, Higher, 2019 · spec 4.4.3.3
Examiner reportSome stated that the melting point is lowered by cryolite, which was not accepted; the melting point of aluminium oxide is a fixed value.AQA GCSE Chemistry Paper 1, Foundation, 2025 · spec 4.4.3.3
4.5 Energy changes16
Mark schemeBecause zinc is in excess (allow because copper sulfate is used up)AQA GCSE Chemistry Paper 1, Higher, 2024 · spec 4.5.1.1
Mark schemeDependent variable: (lowest) temperature reached by the solution (allow change in temperature)AQA GCSE Chemistry Paper 1, Foundation, 2023 · spec 4.5.1.1
Mark schemeOverall temperature change = 2.4 °C (allow ecf from the student's own graph; allow 2.2 °C if no other mark awarded)AQA GCSE Chemistry Paper 1, Foundation, 2020 · spec 4.5.1.1
Mark schemePolystyrene is a better (thermal) insulator (allow converse statements for glass)AQA GCSE Chemistry Paper 1, Higher, 2024 · spec 4.5.1.1
Mark schemeSo there is no additional reaction (allow the reaction has finished)AQA GCSE Chemistry Paper 1, Higher, 2024 · spec 4.5.1.1
Mark schemeThe temperature rises because the reaction is exothermic (allow energy transferred to the surroundings)AQA GCSE Chemistry Paper 1, Higher, 2024 · spec 4.5.1.1
Mark schemeUntil 0.8 g of zinc is added (allow until the temperature reaches 47 degrees C)AQA GCSE Chemistry Paper 1, Higher, 2024 · spec 4.5.1.1
Mark schemeReason: the two metals must be different to produce a voltage (allow the voltage is 0.0 V)AQA GCSE Chemistry Paper 1, Foundation, 2025 · spec 4.5.2.1
Mark schemeHydrogen is oxidised (electrochemically) (allow hydrogen loses electrons)AQA GCSE AQA past paper · spec 4.5.2.2
Mark schemeCorrect value of Y = 7.5 (allow 7.6 from a valid alternative method treating 7.3 as anomalous)AQA GCSE Combined Science Chemistry Paper 1, Foundation, 2023 · spec 5.5.1.1
Mark schemeFrom 0 to 1.5 minutes the temperature decreases (allow decreases from 21.4 C to 15.4 C)AQA GCSE Combined Science Chemistry Paper 1, Higher, 2021 · spec 5.5.1.1
Mark schemeThen after 1.5 minutes the temperature increases (allow after 15.4 C the temperature increases)AQA GCSE Combined Science Chemistry Paper 1, Higher, 2021 · spec 5.5.1.1
Examiner reportCommon correct responses were: • Better insulator • Less heat loss Common responses seen that were not credited included: • good insulator • no heat loss.AQA GCSE Chemistry Paper 1, Higher, 2019 · spec 4.5.1.1
Examiner reportSome referred in general terms to these processes but often used incorrect terms, for example, more energy was needed for making bonds than used for breaking bonds.AQA GCSE Chemistry Paper 1, Higher, 2019 · spec 4.5.1.3
Examiner reportThere was a multitude of ways of establishing that 4 cells were needed, rather than simply dividing the total voltage required by the voltage produced by one cell.AQA GCSE Chemistry Paper 1, Foundation, 2025 · spec 4.5.2.1
Examiner reportMerely making comparisons from the information in the table was insufficient to gain credit.AQA GCSE Chemistry Paper 1, Higher, 2025 · spec 4.5.2.2
4.6 The rate and extent of chemical change23
Mark scheme(Because) a reactant has been used up (allow named reactant, eg zinc or acid used up)AQA GCSE Chemistry Paper 2, Higher, 2021 · spec 4.6.1.1
Mark schemeBetween 80 and 100 seconds, there is no change in the volume of gas (allow reaction stops)AQA GCSE Chemistry Paper 2, Foundation, 2020 · spec 4.6.1.1
Mark schemeThe reaction has stopped (allow no more gas is (being) produced)AQA GCSE Chemistry Paper 2, Higher, 2021 · spec 4.6.1.1
Mark schemeBecause particles have more energy (allow particles move faster)AQA GCSE Chemistry Paper 2, Higher, 2025 · spec 4.6.1.2
Mark schemeBecause the concentration of the reactants decreases — must specify "reactants", not just unspecified "concentration"AQA GCSE Chemistry Paper 2, Higher, 2022 · spec 4.6.1.2
Mark schemeSo particles collide more frequently (allow a greater proportion collide with sufficient energy to exceed the activation energy)AQA GCSE Chemistry Paper 2, Higher, 2025 · spec 4.6.1.2
Mark schemeThe rate (of decomposition/reaction) increases at higher temperatures (allow converse)AQA GCSE Chemistry Paper 2, Higher, 2025 · spec 4.6.1.3
Mark schemeSo the rate of reaction is higher using catalyst B (allow converse for A)AQA GCSE Chemistry Paper 2, Higher, 2025 · spec 4.6.1.4
Mark schemeThe activation energy using catalyst B is lower (allow converse for A)AQA GCSE Chemistry Paper 2, Higher, 2025 · spec 4.6.1.4
Mark schemeLow pressure shifts the equilibrium (position) to the right (allow converse)AQA GCSE Chemistry Paper 2, Higher, 2025 · spec 4.6.2.4
Mark schemeWhich increases the yield of products (allow a high temperature increases the rate of reaction)AQA GCSE Chemistry Paper 2, Higher, 2025 · spec 4.6.2.6
Mark schemeAs the reaction proceeds there are fewer (sodium thiosulfate) particles per unit volume (allow concentration decreases)AQA GCSE Combined Science Chemistry Paper 2, Higher, 2022 · spec 5.6.1.2
Mark schemeWhich is a solid (allow insoluble/a precipitate)AQA GCSE Combined Science Chemistry Paper 2, Higher, 2025 · spec 5.6.1.2
Mark schemeTime = 210 (s) (allow a value in the range 205 to 210)AQA GCSE Combined Science Chemistry Paper 2, Higher, 2024 · spec 5.6.2.3
Examiner reportA ‘successful’ collision was considered insufficient to describe particles whose energy of collision exceeded the activation energy.AQA GCSE Chemistry Paper 2, Higher, 2024 · spec 4.6.1.2
Examiner reportOnly a small proportion of students referred to collisions between particles and, of those that did, a significant minority referred to 'more collisions', which was insufficient for the mark, or incorrectly justified the increased collision frequency in terms of the particles having more energy.AQA GCSE Chemistry Paper 2, Higher, 2020 · spec 4.6.1.3
Examiner reportA few students incorrectly said that the gas evaporated, which was not accepted.AQA GCSE Chemistry Paper 2, Higher, 2025 · spec 4.6.1.4
Examiner reportReferences to changes in the number of collisions were insufficient as they did not answer the question.AQA GCSE Chemistry Paper 2, Higher, 2023 · spec 4.6.1.4
Examiner reportStudents needed to say the activation energy was lower using B. Saying catalyst B requires a lower activation energy was also not accepted, because a catalyst provides or allows a lower activation energy rather than requiring or needing one.AQA GCSE Chemistry Paper 2, Higher, 2025 · spec 4.6.1.4
Examiner reportNo credit was given for a bar chart as the first point had already been plotted for the students to follow.AQA GCSE Combined Science Chemistry Paper 2, Foundation, 2021 · spec 5.6.1.2
Examiner reportTo reach Level 2, three key steps, or two with control variables, were required. To achieve Level 3 marks, all key steps and control variables were needed. This is insufficient for a control variable, but in the final bullet point the ‘same mass’ has been identified, so there is one control variable here.AQA GCSE Combined Science Chemistry Paper 2, Foundation, 2024 · spec 5.6.1.2
Examiner reportStudents tended to describe the action of a catalyst but then failed to address the question of their effect upon the equilibrium position, for which they gained no credit.AQA GCSE Combined Science Chemistry Paper 2, Higher, 2021 · spec 5.6.1.4
Examiner reportThe most common insufficient response was for saying that the reaction was at equilibrium, which it may be but in industry often is not.AQA GCSE Combined Science Chemistry Paper 2, Higher, 2023 · spec 5.6.1.4
4.7 Organic chemistry13
Mark schemeHeater: evaporation (allow liquid to gas / boiling)AQA GCSE Chemistry Paper 2, Foundation, 2025 · spec 4.7.1.2
Mark schemeSo nonane condenses where the column has a higher temperature (allow collects there)AQA GCSE Chemistry Paper 2, Foundation, 2021 · spec 4.7.1.2
Mark schemeFully and correctly balanced: C9H20 + 14O2 → 9CO2 + 10H2O (allow correct multiples)AQA GCSE Chemistry Paper 2, Higher, 2022 · spec 4.7.1.3
Mark schemeCondition: high temperature (allow a stated temperature 300–900°C)AQA GCSE Chemistry Paper 2, Higher, 2022 · spec 4.7.1.4
Mark schemeHexane: bromine water remains orange (allow no colour change)AQA GCSE Chemistry Paper 2, Foundation, 2020 · spec 4.7.1.4
Mark schemeHigh temperature (allow a value in the range 300-900°C)AQA GCSE Chemistry Paper 2, Higher, 2021 · spec 4.7.1.4
Mark schemeThe bromine water is (initially) orange (allow yellow/brown)AQA GCSE Chemistry Paper 2, Higher, 2024 · spec 4.7.1.4
Mark schemeAnaerobic conditions (allow without oxygen/air)AQA GCSE Chemistry Paper 2, Higher, 2021 · spec 4.7.2.3
Mark schemeWarm (temperature) (allow a value in the range 25°C to 45°C)AQA GCSE Chemistry Paper 2, Higher, 2021 · spec 4.7.2.3
Mark schemeThe alkene used to produce poly(propene) is propene (allow "a monomer")AQA GCSE Chemistry Paper 2, Foundation, 2020 · spec 4.7.3.1
Mark schemePetrol has a lower boiling point (range) than diesel (or the converse); allow petrol is more flammable / less viscous than dieselAQA GCSE Combined Science Chemistry Paper 2, Foundation, 2023 · spec 5.7.1.3
Examiner reportA statement about heavy fuel oil being more viscous than kerosene was insufficient for credit because this repeated information given in the question.AQA GCSE Chemistry Paper 2, Higher, 2022 · spec 4.7.1.3
Examiner reportMany students rewrote the information provided in the rubric without elaboration, for which no credit was given.AQA GCSE Combined Science Chemistry Paper 2, Foundation, 2021 · spec 5.7.1.1
4.8 Chemical analysis19
Mark schemeAllow the solvent/dyes to travel up the paper (until near the top)AQA GCSE Chemistry Paper 2, Foundation, 2022 · spec 4.8.1.3
Mark schemeThe solvent level must be below the start lineAQA GCSE Chemistry Paper 2, Foundation, 2021 · spec 4.8.1.3
Mark schemeTest: hold a lit / burning splint at the mouth of the test tube (do not accept a glowing splint)AQA GCSE Chemistry Paper 2, Foundation, 2023 · spec 4.8.2.1
Mark schemeTest: bubble the gas through limewater (allow calcium hydroxide solution)AQA GCSE Chemistry Paper 2, Higher, 2025 · spec 4.8.2.3
Mark schemeResult: the litmus paper is bleached / turns white (ignore litmus turning red)AQA GCSE Chemistry Paper 2, Higher, 2025 · spec 4.8.2.4
Mark schemeResult: yellow flame (allow lines match the sodium spectrum, for flame emission spectroscopy)AQA GCSE Chemistry Paper 2, Foundation, 2024 · spec 4.8.3.1
Mark schemeTest: carry out a flame test (allow a description of the flame test procedure)AQA GCSE Chemistry Paper 2, Higher, 2021 · spec 4.8.3.1
Mark schemeTest: flame test (allow flame emission spectroscopy / FES)AQA GCSE Chemistry Paper 2, Foundation, 2024 · spec 4.8.3.1
Mark schemeCalcium iodide solution: white precipitate (allow white solid)AQA GCSE Chemistry Paper 2, Foundation, 2020 · spec 4.8.3.2
Mark schemeCopper sulfate solution: blue precipitate (allow blue solid)AQA GCSE Chemistry Paper 2, Foundation, 2020 · spec 4.8.3.2
Mark schemeResult: with sodium hydroxide the (white) precipitate dissolves (allow a colourless solution is produced)AQA GCSE Chemistry Paper 2, Higher, 2025 · spec 4.8.3.2
Mark schemeResult: (pale) yellow precipitate (allow yellow solid)AQA GCSE Chemistry Paper 2, Foundation, 2020 · spec 4.8.3.4
Mark schemeAdd barium chloride solution (allow barium nitrate solution)AQA GCSE Chemistry Paper 2, Higher, 2021 · spec 4.8.3.5
Mark schemeAdd dilute hydrochloric acid (allow dilute nitric acid)AQA GCSE Chemistry Paper 2, Higher, 2021 · spec 4.8.3.5
Mark schemeStates the distance moved by the red colour is 3.2 cm (allow a value in the range 3.1 to 3.3 cm, or 32 mm)AQA GCSE Combined Science Chemistry Paper 2, Foundation, 2024 · spec 5.8.1.3
Examiner reportAlmost 30% of students obtained one mark usually by correctly identifying the mistake as using ink but providing an insufficient reason for the mistake such as mix, ruin, or affect the result.AQA GCSE Chemistry Paper 2, Foundation, 2024 · spec 4.8.1.3
Examiner reportpale/light blue, but answers giving two colours such as green/blue were not credited.AQA GCSE Chemistry Paper 2, Foundation, 2022 · spec 4.8.3.2
Examiner reportOther answers referring to instrumental methods as being more exact, reliable, repeatable, reproducible, efficient or reducing human error were considered too vague.AQA GCSE Chemistry Paper 2, Higher, 2024 · spec 4.8.3.6
Examiner reportCommon insufficient responses included heat for longer, whilst giving no reasoning, heat for shorter time, or put a lid on.AQA GCSE Combined Science Chemistry Paper 2, Higher, 2023 · spec 5.8.2.2
4.9 Chemistry of the atmosphere26
Mark schemeBecause carbon dioxide dissolved in the oceans, or because of the formation of carbonate precipitates/sediments — do not accept references to photosynthesisAQA GCSE Chemistry Paper 2, Higher, 2022 · spec 4.9.1.2
Mark schemeUntil about 2.3 billion years (allow 2.1-2.4 billion years, or until about 80%)AQA GCSE Chemistry Paper 2, Foundation, 2024 · spec 4.9.1.2
Mark schemeBy algae/plants (allow cyanobacteria)AQA GCSE Chemistry Paper 2, Higher, 2025 · spec 4.9.1.3
Mark schemeSubjected to high temperature and high pressure (over millions of years) — "heat" alone is insufficient, must specify high temperatureAQA GCSE Chemistry Paper 2, Higher, 2022 · spec 4.9.1.4
Mark schemeBecause of emission from volcanoes (allow denitrifying bacteria)AQA GCSE Combined Science Chemistry Paper 2, Higher, 2022 · spec 5.9.1.2
Mark schemePlankton died (allow remains of ancient biomass)AQA GCSE Combined Science Chemistry Paper 2, Higher, 2024 · spec 5.9.1.4
Mark schemeGreenhouse gases allow short wavelength radiation to enter the atmosphereAQA GCSE Combined Science Chemistry Paper 2, Higher, 2023 · spec 5.9.2.1
Mark schemeGives the year (1850, allow a value in the range 1850 to 1865) when the increase startsAQA GCSE Combined Science Chemistry Paper 2, Foundation, 2024 · spec 5.9.2.2
Mark scheme(Some) fuels contain sulfur (allow a named fossil fuel)AQA GCSE Combined Science Chemistry Paper 2, Higher, 2024 · spec 5.9.3.1
Mark schemeFuels are burnt (allow a named fossil fuel)AQA GCSE Combined Science Chemistry Paper 2, Higher, 2024 · spec 5.9.3.1
Mark schemeIn insufficient / limited oxygen (allow produced by incomplete combustion)AQA GCSE Combined Science Chemistry Paper 2, Higher, 2024 · spec 5.9.3.1
Mark schemeAcid rain (allow a specific effect of acid rain)AQA GCSE Combined Science Chemistry Paper 2, Higher, 2024 · spec 5.9.3.2
Mark schemeCauses acid rain (allow specified damage caused by acid rain, eg damages buildings/statues, kills fish, damages trees/plants, acidifies soil/lakes)AQA GCSE Combined Science Chemistry Paper 2, Foundation, 2022 · spec 5.9.3.2
Mark schemeCauses respiratory problems (allow a named respiratory problem, eg asthma, breathing difficulties)AQA GCSE Combined Science Chemistry Paper 2, Foundation, 2022 · spec 5.9.3.2
Mark schemeRespiratory problems in humans (allow a named respiratory problem, eg asthma)AQA GCSE Combined Science Chemistry Paper 2, Higher, 2024 · spec 5.9.3.2
Examiner reportResponses therefore in terms of ammonia were insufficient.AQA GCSE Chemistry Paper 2, Higher, 2022 · spec 4.9.1.2
Examiner reportMany gave the description of photosynthesis, but this was insufficient for the mark.AQA GCSE Chemistry Paper 2, Higher, 2025 · spec 4.9.1.3
Examiner reportThe ideas of more sugar or plants being needed to carry out more photosynthesis to remove more carbon dioxide were needed.AQA GCSE Chemistry Paper 2, Foundation, 2022 · spec 4.9.1.3
Examiner reportSome students were insufficiently precise about the size of the organisms involved in natural gas formation, and there was some confusion with the formation of coal.AQA GCSE Chemistry Paper 2, Higher, 2022 · spec 4.9.1.4
Examiner reportIncorrect or insufficient responses included ‘heating the limestone’ and general references to the equation, or that methane might escape during its combustion.AQA GCSE Chemistry Paper 2, Foundation, 2024 · spec 4.9.2.2
Examiner reportA number of students knew that this was incomplete combustion but far fewer mentioned insufficient oxygen.AQA GCSE Chemistry Paper 2, Higher, 2020 · spec 4.9.3.1
Examiner reportOf those who did realise that oxygen and nitrogen were reacting, some thought that this was happening outside the car rather than in the engine and very few mentioned that a high temperature was needed, some just referring to heat.AQA GCSE Chemistry Paper 2, Higher, 2020 · spec 4.9.3.1
Examiner report‘No proof’ alone was insufficient to gain credit.AQA GCSE Combined Science Chemistry Paper 2, Foundation, 2021 · spec 5.9.1.2
Examiner reportNo credit was given for the common answer of “The Earth gets hotter” as the response needed to be a for consequence of this.AQA GCSE Combined Science Chemistry Paper 2, Foundation, 2021 · spec 5.9.2.3
Examiner reportHeat from the engine was insufficient to gain marking point 1 as there must be an indication of high temperature.AQA GCSE Combined Science Chemistry Paper 2, Higher, 2021 · spec 5.9.3.1
Examiner reportThere were many responses that answered as an absolute rather than a comparison which was insufficient for the mark.AQA GCSE Combined Science Chemistry Paper 2, Foundation, 2025 · spec 5.9.3.1
4.10 Using resources38
Mark schemeMining / quarrying (for ore) causes environmental impacts (allow a described environmental impact of mining/quarrying)AQA GCSE Chemistry Paper 2, Higher, 2021 · spec 4.10.1.1
Mark schemeNitrogen is an abundant gas in the air (allow nitrogen is renewable)AQA GCSE Chemistry Paper 2, Higher, 2025 · spec 4.10.1.1
Mark schemeMass of evaporating dish measured using a (mass) balance (allow scales)AQA GCSE Chemistry Paper 2, Foundation, 2021 · spec 4.10.1.2
Mark schemeMean concentration of Na+ = 13.8 (g/dm3) (allow 13.755 correctly rounded to at least 3 sig figs)AQA GCSE Chemistry Paper 2, Foundation, 2024 · spec 4.10.1.2
Mark schemeVolume of sea water measured using a measuring cylinder (allow burette/pipette)AQA GCSE Chemistry Paper 2, Foundation, 2021 · spec 4.10.1.2
Mark schemeConserves energy / resources (allow more sustainable)AQA GCSE Chemistry Paper 2, Foundation, 2020 · spec 4.10.1.3
Mark schemeIncreased demand for food, due to increasing population (allow more farming)AQA GCSE Chemistry Paper 2, Foundation, 2020 · spec 4.10.1.3
Mark schemeIncreased demand for organic fertiliser (allow lifestyle choice for organic food)AQA GCSE Chemistry Paper 2, Foundation, 2020 · spec 4.10.1.3
Mark schemeLandfill space is running out (allow awareness of negative environmental impacts of landfill)AQA GCSE Chemistry Paper 2, Foundation, 2020 · spec 4.10.1.3
Mark schemeElectrolysis of the solution, or displacement of copper from the solution (allow addition of scrap iron to the solution)AQA GCSE Chemistry Paper 2, Higher, 2021 · spec 4.10.1.4
Mark schemeGrow plants on land containing copper ores (allow a named plant)AQA GCSE Chemistry Paper 2, Higher, 2021 · spec 4.10.1.4
Mark schemeIt is new technology (allow demand is not high enough)AQA GCSE Chemistry Paper 2, Higher, 2021 · spec 4.10.1.4
Mark schemeRecycling reduces waste (allow reduces use of landfill)AQA GCSE Chemistry Paper 2, Higher, 2021 · spec 4.10.1.4
Mark schemeThe aluminium alloy frame has a shorter lifespan, so must be replaced more frequentlyAQA GCSE Chemistry Paper 2, Higher, 2024 · spec 4.10.2.1
Mark schemePaper plates are single-use so must be replaced most often; ceramic plates last longer than polymer plates so are replaced less oftenAQA GCSE Chemistry Paper 2, Higher, 2020 · spec 4.10.2.2
Mark schemeRecycling conserves copper ores (allow copper ores are finite)AQA GCSE Chemistry Paper 2, Higher, 2021 · spec 4.10.2.2
Mark schemeBecause pre-stressed concrete is stronger (do not accept because it is more dense)AQA GCSE Chemistry Paper 2, Foundation, 2024 · spec 4.10.3.3
Mark schemeLong chain molecules (allow long chains of monomers)AQA GCSE Chemistry Paper 2, Higher, 2025 · spec 4.10.3.3
Mark schemePre-stressed concrete can bear the weight of heavy traffic (allow the bridge is less likely to collapse)AQA GCSE Chemistry Paper 2, Foundation, 2024 · spec 4.10.3.3
Mark schemeWith covalent bonds between the chains (allow cross-links between the chains; ignore intermolecular forces)AQA GCSE Chemistry Paper 2, Higher, 2025 · spec 4.10.3.3
Mark schemeFinal answer of approximately 62.5 dm3 (allow a value in the range 62 to 65)AQA GCSE Chemistry Paper 2, Higher, 2025 · spec 4.10.4.1
Mark schemeHydrogen comes from natural gas / methane — do not accept the atmosphere as the source of hydrogenAQA GCSE Chemistry Paper 2, Higher, 2022 · spec 4.10.4.1
Mark schemeSo that only ammonia liquefies / condenses (because it has a higher boiling point than nitrogen and hydrogen) — do not accept ammonia has a lower boiling pointAQA GCSE Chemistry Paper 2, Higher, 2022 · spec 4.10.4.1
Mark schemeWith phosphoric acid: calcium phosphate (allow triple superphosphate)AQA GCSE Chemistry Paper 2, Higher, 2023 · spec 4.10.4.2
Mark schemeWith sulfuric acid: calcium sulfate (allow single superphosphate)AQA GCSE Chemistry Paper 2, Higher, 2023 · spec 4.10.4.2
Examiner reportWeaker responses referred to ‘pollution’ alone which was too vague to gain credit.AQA GCSE Chemistry Paper 2, Foundation, 2022 · spec 4.10.1.1
Examiner reportStudents needed to state that the microbes were harmful and because of this some did not gain the first mark, although many were awarded the second.AQA GCSE Chemistry Paper 2, Higher, 2022 · spec 4.10.1.2
Examiner reportResponses referring to ‘heating the wire’ were insufficient to gain credit.AQA GCSE Chemistry Paper 2, Foundation, 2022 · spec 4.10.2.2
Examiner reportA correct test was needed to allow award of a mark for the test result.AQA GCSE Chemistry Paper 2, Foundation, 2024 · spec 4.10.4.1
Examiner reportAnswers not gaining credit often related to time, or were imprecise; for example, for a mention of temperature to gain a mark, the student had to state that the temperature was too low, not just different.AQA GCSE Chemistry Paper 2, Foundation, 2019 · spec 4.10.4.1
Examiner reportTherefore, a reasoned judgement was needed to access Level 3.AQA GCSE Chemistry Paper 2, Higher, 2023 · spec 4.10.4.2
Examiner reportThis was another question where students were required to interpret information provided.AQA GCSE Combined Science Chemistry Paper 2, Foundation, 2022 · spec 5.10.1.1
Examiner reportIt is insufficient to simply state that a pure substance is only made up of one type of substance. No credit was given the latter being an easier process or taking less time.AQA GCSE Combined Science Chemistry Paper 2, Higher, 2021 · spec 5.10.1.2
Examiner reportA comparison of the proportion of carbon in each fuel source was required for the mark.AQA GCSE Combined Science Chemistry Paper 2, Higher, 2022 · spec 5.10.1.4
Examiner reportThose that did state displacement often gave an insufficient answer, not including that this process uses iron or giving an incorrect element such as carbon.AQA GCSE Combined Science Chemistry Paper 2, Higher, 2024 · spec 5.10.1.4
Examiner reportDirect comparisons only allowed access to level 1, however, and links to the problems caused were required to make further progress. A judgement (which many students gave) and comparisons of both economic and environmental factors was required to do this.AQA GCSE Combined Science Chemistry Paper 2, Higher, 2022 · spec 5.10.2.1
Examiner reportDistinctions should be made between whether the data relates to required resources or waste produced, as a number of students did not make the distinction which meant some responses could not be credited.AQA GCSE Combined Science Chemistry Paper 2, Foundation, 2022 · spec 5.10.2.1
Examiner reportSimply repeating data from the table without interpretation or using it was common and was not credited.AQA GCSE Combined Science Chemistry Paper 2, Foundation, 2024 · spec 5.10.2.2
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