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The 6-mark extended-response questions are the highest-tariff items on both Paper 1 and Paper 2, and they are marked differently from every other question. Instead of a point-by-point mark scheme, the examiner uses a levels-of-response mark scheme: your whole answer is read and placed in a level (Level 1, 2 or 3) based on how much correct, relevant, well-organised science it contains. This means the structure, coherence and scientific language of your answer matter just as much as the facts. A jumbled answer with correct points can score below a well-organised answer with the same content.
By the end of this lesson you should understand how the level descriptors work, be able to plan and sequence a 6-mark answer, know how to cover both sides of an "evaluate" question, and be able to lift a response from the middle band to the top band.
Examiners use a three-level mark scheme. The exact wording varies by question, but the shape is always like this:
| Level | Marks | What it rewards |
|---|---|---|
| Level 3 | 5–6 | A detailed, coherent answer showing thorough understanding. Correct terminology throughout. Logically structured, with ideas clearly linked. For "evaluate", a supported conclusion. |
| Level 2 | 3–4 | Reasonable understanding. Some correct terminology. Some structure, but links may be incomplete or the answer one-sided. |
| Level 1 | 1–2 | Limited understanding. Simple, mostly isolated statements with little linking. Terminology absent or misused. |
| 0 | 0 | No relevant content. |
The key insight: moving up a level is not just about adding more facts — it is about linking them into a logical chain and using the right vocabulary. Three connected, well-expressed points beat six disconnected ones.
Exam Tip: Level descriptors reward coherence and linkage, not a longer list. Before you write, decide the order your points should go in so each one leads to the next.
A planned answer almost always outscores an unplanned one. Spend the first 60–90 seconds planning:
A sensible time budget for a 6-marker is about 7 minutes: ~30 s to read and underline, ~90 s to plan, ~4.5 min to write, ~30 s to check.
Exam Tip: For an evaluate 6-marker, plan two columns — for and against — and a one-line conclusion before you write a word. That guarantees you cover both sides and finish with the judgement the top level demands.
Take: "Describe how you would make pure, dry crystals of copper sulfate from copper oxide and sulfuric acid. (6 marks)."
A margin plan might read:
Six ordered steps, each leading to the next — that is a Level 3 skeleton before any prose is written.
Question (6 marks): A reaction between two solutions causes the temperature to rise. Explain, in terms of energy and bonds, why some reactions are exothermic and others are endothermic, and describe how you could investigate the temperature change of a reaction in the laboratory.
This question links energy changes (C3/C5) with practical technique. The three responses below show the same question answered at three levels.
Mid-band response: "Exothermic reactions give out heat so the temperature goes up, and endothermic reactions take in heat so the temperature goes down. It is to do with bonds breaking and making. To investigate it you mix the two solutions in a cup and measure the temperature with a thermometer before and after to see if it goes up or down."
Examiner-style commentary: A sound Level 2 answer. It correctly contrasts exothermic and endothermic in terms of temperature and gestures at bonds, and the outline method is workable. To climb to Level 3 it needs the energy detail — that breaking bonds is endothermic (takes in energy) and making bonds is exothermic (releases energy), and that the overall energy change decides the type — plus a more precise method (insulated cup, fixed volumes, record the temperature change).
Stronger response: "In a chemical reaction, energy is taken in to break the bonds in the reactants and energy is released when new bonds form in the products. If more energy is released making bonds than is taken in breaking them, the reaction is exothermic and the temperature of the surroundings rises. If more energy is taken in breaking bonds than is released, the reaction is endothermic and the temperature falls. To investigate this, measure a fixed volume of one solution into an insulated polystyrene cup, record the starting temperature, add a fixed volume of the second solution, stir, and record the highest or lowest temperature reached. The temperature change shows whether the reaction is exothermic (rise) or endothermic (fall)."
Examiner-style commentary: A strong Level 3 answer: the bond-energy reasoning is correct and clearly linked to the temperature change, and the method is detailed with sensible apparatus. To make it watertight at the top of Level 3 it could add why the cup is insulated (to reduce heat loss to the surroundings, so the temperature change measured is accurate) and mention repeating the experiment to improve repeatability.
Top-band response: "Whether a reaction is exothermic or endothermic depends on the balance between the energy needed to break bonds and the energy released when new bonds form. Breaking bonds in the reactants is an endothermic process — it requires energy — while forming bonds in the products is an exothermic process that releases energy. If the energy released when bonds form is greater than the energy taken in to break bonds, there is a net release of energy to the surroundings: the reaction is exothermic and the temperature of the surroundings rises (for example, neutralisation or combustion). If the energy taken in to break bonds is greater than the energy released, there is a net intake of energy from the surroundings: the reaction is endothermic and the temperature falls (for example, some dissolving reactions). To investigate the temperature change, I would use a polystyrene cup with a lid as a calorimeter to minimise heat loss, measure a known volume of the first solution with a measuring cylinder, record its initial temperature with a thermometer, add a measured volume of the second solution, stir, and record the maximum or minimum temperature. The temperature change (ΔT) shows the type of reaction — a rise indicates exothermic, a fall indicates endothermic — and I would repeat the experiment and take a mean to make the result more repeatable, keeping the volumes and concentrations the same each time as control variables."
Examiner-style commentary: Full marks. The energy reasoning is complete and correct (bond breaking endothermic, bond making exothermic, net change deciding the type), each idea is linked to the temperature change with worked examples, and the method is precise, justified (insulation to reduce heat loss) and controlled (fixed volumes, repeats and a mean). The accurate terminology and logical flow from theory to method are exactly what lift an answer to the top of Level 3.
Not every 6-marker is built the same way. The command word tells you which shape the top-band answer should take, and choosing the wrong shape is a common reason able students stall at Level 2.
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