Exam-style Questions: Extraction of Metals

 

  1. The diagram below shows the blast furnace:

    Exam-style Questions

    a) Complete the labels A, B and C.

    (3 marks)

    b) What are the main waste gases from the blast furnace?

    (2 marks)

    (Marks available: 5)

    Answer

     

    Answer outline and marking scheme for question: 1

    a) A = iron ore

    (1 mark)

    B = slag

    (1 mark)

    C = molten iron

    (1 mark)

    b) Carbon dioxide

    (1 mark)

    Nitrogen

    (1 mark)

    (Total = 5 marks)

  2. The following questions are about the blast furnace and the production of iron.

    a) Why are hot blasts of air blown in to the blast furnace?

    (1 mark)

    b) Why is limestone added to the blast furnace?

    (1 mark)

    c) Railway lines are welded together using molten iron.

    The molten iron is made using the 'thermit' reaction where iron oxide is reacted with aluminium powder.

    Why is this reaction not used to make iron on a large scale?

    (1 mark)

    (Marks available: 3)

    Answer

     

    Answer outline and marking scheme for question: 2

    a) The air is used to react with the coke/carbon to form carbon dioxide.

    (1 mark)

    b) To remove the impurities that are in the iron ore/to form slag.

    (1 mark)

    c) Any one from:

    • Too expensive/aluminium is more expensive than iron.
    • Too dangerous/aluminium reacts violently with iron oxide.

     

    (1 mark)

    (Total = 3 marks)

  3. Aluminium metal is produced using electrolysis.

    The cell used in this process is shown below:

    Exam-style Questions

    a) Complete the labels A, B and C.

    (3 marks)

    b) Why is cryolite added to the aluminium ore in this process?

    (1 mark)

    (Marks available: 4)

    Answer

     

    Answer outline and marking scheme for question: 3

    a) A = graphite electrodes.

    (1 mark)

    B = molten bauxite/aluminium ore.

    (1 mark)

    C = molten aluminium metal.

    (1 mark)

    b) To lower the melting point of the aluminium oxide (so less energy required).

    (1 mark)

    (Total = 4 marks)

  4. The following questions are about the electrolysis of aluminium oxide.

    a) Why does the anode need to be replaced regularly?

    (1 mark)

    b) Write an equation to show how aluminium ions are changed in to aluminium metal.

    (2 marks)

    c) Why can't the blast furnace be used to make aluminium?

    (1 mark)

    (Marks available: 4)

    Answer

     

    Answer outline and marking scheme for question: 4

    a) The carbon/graphite anode reacts with the oxygen made to form carbon dioxide gas.

    (1 mark)

    b) Al3+(l) + 3e- → Al(l)

     

    (1 mark = formulae, 1 mark = balanced)

    c) Aluminium is more reactive than carbon (not too reactive).

    (1 mark)

    (Total = 4 marks)