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.

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.

Sample question 1 - Foundation

Question

Metals are extracted by different methods which are linked to their position in the reactivity series of metals:

  • iron is extracted from iron oxide by heating with carbon
  • gold is found uncombined in the Earth's crust
  • aluminium is extracted from aluminium oxide using electrolysis.

The list shows part of the reactivity series with iron, gold and aluminium missing.

  • calcium
  • magnesium
  • ______
  • zinc
  • ______
  • tin
  • lead
  • ______

Use the information given about the methods of extracting these metals to explain where in this reactivity series iron, gold and aluminium are placed. [6 marks]

Edexcel question courtesy of Pearson Education Ltd.

Your answer should include the following:

Gold:

  • gold is found uncombined as it doesn't react easily
  • gold is least reactive
  • gold is placed in the lowest position

Aluminium:

  • electricity needed to extract aluminium
  • electricity is the most powerful method (of extraction)
  • aluminium is very reactive/most reactive
  • aluminium is more reactive than carbon
  • aluminium is placed in the highest position

Iron:

  • carbon is more reactive than iron
  • (hot) carbon reduces iron oxide
  • (hot) carbon does not reduce aluminium oxide
  • iron is less reactive than aluminium
  • iron is not found as an uncombined metal
  • iron is more reactive than gold
  • iron is placed in the middle position

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Sample question 2 - Higher

Question

Iron for making steel, copper and aluminium is obtained from substances found in the Earth's crust.

The metals are made into many useful things. When no longer required, the metal articles are thrown away as waste or recycled.

Explain why it is important to recycle these metals, rather than put them in general household waste. [6 marks]

Edexcel question courtesy of Pearson Education Ltd.

Your answer should include the following:

  • copper used for pipes/wiring/vehicles
  • aluminium used for cans/wires/alloys
  • steel used for bridges/making stainless steel cutlery
  • recycled metals can be made into something useful
  • saves (finite) resources/stops the metal (ore) running out
  • less damage to environment by mining/quarrying
  • less waste
  • landfill sites will not fill up as quickly
  • (some) metals do not corrode/break down so they remain a long time in landfill
  • if recycled, fewer landfills needed
  • less damage to environment from waste
  • copper waste is toxic
  • less expensive than extraction from ores/electrolysis

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Sample question 3 - Foundation

Question

The order of reactivity of magnesium, zinc and copper can be determined by carrying out displacement reactions.

Explain how displacement reactions can be used to show the reactivity of these three elements. [6 marks]

This question has been written by a Bitesize consultant as a suggestion to the type of question that may appear in an exam paper.

Your answer should include the following:

Order of reactivity - magnesium > zinc > copper.

The order of reactivity supported by suitable experiments from:

  • add magnesium to suitable solutions, eg magnesium sulfate, zinc sulfate, copper sulfate
    • black coating of zinc on magnesium in zinc solution
    • brown coating of copper on magnesium in copper solution
    • magnesium is more reactive than zinc and copper
  • add zinc to suitable solutions, eg magnesium sulfate, zinc sulfate, copper sulfate
    • brown coating of copper on zinc in copper solution
    • no visible reaction in magnesium and zinc solutions
    • zinc is more reactive than copper but less reactive than magnesium
  • add copper to suitable solutions, eg magnesium sulfate, zinc sulfate, copper sulfate
    • no visible reaction in these solutions
    • copper is less reactive than magnesium and zinc

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Sample question 4 - Higher

Question

Metals are obtained from the Earth's crust by different methods.

Some metals are found uncombined but others have to be extracted from their ores by electrolysis or by heating the ore with carbon.

Explain, using aluminium, gold and iron as examples, how the method used to obtain the metal is related to its position in the reactivity series and to the cost of the extraction process. [6 marks]

Edexcel question courtesy of Pearson Education Ltd.

Your answer should include the following:

Gold:

  • gold is an unreactive metal/at the bottom of the reactivity series
  • it does not combine with other elements in the Earth's crust
  • so is found as uncombined metal
  • cost of recovery is low

Iron:

  • iron is a more reactive metal than gold and less reactive than aluminium/middle of reactivity series
  • found combined with other elements
  • it is extracted by heating with carbon
  • carbon is more reactive than iron
  • electrolysis can be used
  • but electrolysis is more expensive (than heating with carbon)

Aluminium:

  • aluminium is a very reactive metal/near to top of the reactivity series
  • found combined with other elements
  • aluminium is above carbon in reactivity series
  • aluminium oxide/ores cannot be reduced by heating with carbon
  • it is extracted by electrolysis
  • because it is very difficult to reduce
  • electrolysis is a powerful method of reduction
  • use of electricity makes this method expensive

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