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The 6-mark extended response question is the single most important question type on your Edexcel GCSE Chemistry papers. Each paper will contain at least one 6-mark question, and these are the questions where the difference between a grade 5 and a grade 8 becomes most visible.
Unlike other questions where you earn one mark per correct point, 6-mark questions use levels-based marking. This means the examiner reads your entire answer, decides what level it falls into, and then awards a mark within that level.
| Level | Marks | Description |
|---|---|---|
| Level 3 | 5–6 marks | A comprehensive, well-structured answer with detailed scientific explanation. Correct use of scientific terminology throughout. Logical sequence with clear links between points. |
| Level 2 | 3–4 marks | Some relevant scientific points made but lacks detail or has gaps in the explanation. Some correct terminology. Answer may lack structure or logical flow. |
| Level 1 | 1–2 marks | Simple statements with limited scientific detail. Little or no use of scientific terminology. Answer may be disorganised or incomplete. |
| No level | 0 marks | No relevant content. |
Exam tip: The jump from Level 1 to Level 3 is not about writing more — it is about writing with detail, terminology, and logical structure. A short, precise, well-organised answer can score 6 marks. A long, rambling answer can score 2.
You must include specific scientific facts, not vague generalisations:
| Weak (Level 1) | Strong (Level 3) |
|---|---|
| "The metals react with water" | "Sodium reacts vigorously with water, producing sodium hydroxide and hydrogen gas: 2Na + 2H₂O → 2NaOH + H₂" |
| "It conducts electricity" | "When molten, the ions are free to move and carry charge, allowing an electric current to flow" |
| "The rate gets faster" | "Increasing the temperature increases the kinetic energy of the particles, so they collide more frequently and a greater proportion of collisions exceed the activation energy" |
The examiner is looking for precise, technical language:
Your answer must flow logically. Each point should connect to the next. Use connectives:
While there is no single template that works for every 6-mark question, the following structure works well in most cases:
Introduce the topic and define any key terms.
Write 3–4 detailed points in a logical order. Each point should include a fact, an explanation, and correct terminology.
Link back to the question and provide a clear concluding statement.
"To prepare pure, dry copper sulfate crystals, first warm dilute sulfuric acid in a beaker using a water bath or Bunsen burner. Then add copper oxide powder to the warm acid and stir. Continue adding copper oxide until it is in excess — you can tell it is in excess because some black powder remains undissolved at the bottom of the beaker. This ensures all the acid has reacted.
Next, filter the mixture using filter paper and a funnel to remove the excess copper oxide. The filtrate is the copper sulfate solution.
Pour the filtrate into an evaporating basin and heat gently to evaporate some of the water. Do not boil to dryness — stop heating when crystals begin to appear at the edge of the solution. Leave the solution to cool and allow crystals to form slowly by evaporation at room temperature. Finally, pat the crystals dry with filter paper."
This answer scores Level 3 (6 marks) because it: (1) follows a logical step-by-step sequence, (2) includes key details such as "add excess copper oxide" and "until some remains undissolved," (3) explains why each step is done, and (4) uses correct terminology throughout. The instruction to stop heating before boiling to dryness is an important detail that many students miss.
"Group 1 metals become more reactive as you go down the group. This is because each element going down the group has an additional electron shell. For example, lithium has 2 electron shells, sodium has 3, and potassium has 4.
As the number of electron shells increases, the outer electron is further from the nucleus. This means the electrostatic attraction between the positively charged nucleus and the negatively charged outer electron is weaker, because electrostatic attraction decreases with distance.
As a result, less energy is needed to remove the outer electron, so the atom loses its outer electron more easily. Since Group 1 metals react by losing their outer electron to form a 1+ ion, the metals that lose their electron most easily are the most reactive. Therefore, potassium is more reactive than sodium, which is more reactive than lithium."
This answer scores Level 3 because it: (1) states the trend clearly, (2) explains the mechanism in terms of electron shells, distance from nucleus, and electrostatic attraction, (3) uses correct terminology such as "electrostatic attraction" and "1+ ion," and (4) links the explanation back to the question with a concluding comparative statement.
"Hydrogen is a potential alternative to fossil fuels. When hydrogen burns, the only product is water (2H₂ + O₂ → 2H₂O), so it does not produce carbon dioxide or particulates at the point of use. This means it does not contribute to global warming or air pollution when used in vehicles.
However, most hydrogen is currently produced by reacting methane with steam, which does release carbon dioxide. Hydrogen can also be produced by the electrolysis of water, but this requires a large amount of electrical energy, which may come from fossil fuels.
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