Six-mark questions

Six-mark questions are extended open response questions. These require longer answers than the structured questions. It is wise to plan your answer rather than rushing straight into it, otherwise you may stray away from the key points.

Most questions on exam papers have mark schemes that give key points that are given marks. The six-mark questions are marked differently - they use a levels-based mark scheme. This type of mark scheme is used because these questions are more open-ended. To gain full marks, you need to:

  • support explanations using scientific knowledge and understanding
  • use appropriate scientific words and terms
  • write clearly and link ideas in a logical way
  • maintain a sustained line of reasoning, rather than getting lost or bogged down

Six-mark questions often use these command words:

  • describe - you need to give an account but no reason
  • explain - you must give reasons or explanations
  • devise - you must plan or invent a procedure using your scientific knowledge and understanding
  • evaluate - you must review information, including identifying strengths and weaknesses and make a supported conclusion

Six-mark questions may be synoptic questions. These questions bring together ideas from two or more topics. For example, a question about fertilisers could include ideas about covalent substances, acids and alkalis, chemical calculations and effects on the environment.

The answers shown here give marking points as bullet points. You do not usually need to include all of them to gain six marks, but you do need to write in full sentences, linking them logically and clearly.

Answers are placed in three marking bands:

  • 1 to 2 marks for answers showing limited content and reasoning and with significant omissions.
  • 3 to 4 marks for answers that give some relevant points, with linking and reasoning and with fewer omissions.
  • 5 to 6 marks for answers that link most of the relevant points, with good links and reasoning. They will have few, if any, omissions.

Questions courtesy of Eduqas.

Sample question 1 - Foundation

Question

Describe and explain an investigation you would carry out to find the relative positions of copper, iron and magnesium in the reactivity series. Include equations where appropriate. [6 marks]

You are provided with:

  • solid samples of copper, iron and magnesium
  • solid samples of copper(II) sulfate, iron(II) sulfate and magnesium sulfate

Your answer should include the following:

Description of method:

  • dissolve salts in water
  • add each metal to solution of other two aqueous metal solutions

Expected observations:

  • copper to solutions of iron and magnesium salts - no change
  • iron and copper(II) sulfate - solution turns colourless, coppery coloured deposit
  • no change with magnesium salt
  • magnesium to iron(II) and copper salts - solutions turn colourless
  • copper-coloured deposit with copper(II) solution

Explanation:

  • these are displacement reactions
  • order of metals in reactivity series (magnesium > iron > copper)
  • relevant equations, eg Mg + CuSO4 → MgSO4 + Cu

[6]

Sample question 2 - Higher

Question

An electrolysis cell is used in the extraction of aluminium from molten aluminium oxide.

Describe and explain how this process works, including relevant equations. [6 marks]

Your answer should include the following:

  • aluminium oxide heated until molten
  • cryolite added to lower melting point
  • Al3+ and O2- ions free to move in molten state
  • Al3+ ions attracted to cathode where they gain electrons and form atoms
  • Al3+ + 3e- → Al
  • Molten aluminium falls to bottom of cell
  • O2- ions attracted to anodes
  • O2- ions lose electrons forming oxygen molecules
  • 2O2- → O2 + 4e-
  • overall reaction is 2Al2O3 → 4Al + 3O2

[6]