Calculate — 2 marks
A copper mine extracts copper from copper oxide ore using carbon reduction. In one batch, 80 g of copper oxide (CuO) is heated with excess carbon. The equation for the reaction is: 2CuO + C → 2Cu + CO₂. The relative atomic masses are: Cu = 64, O = 16.
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(a) Calculate the relative formula mass of copper oxide (CuO).
[1 mark]
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(b) Calculate the maximum mass of copper that could be produced from 80 g of copper oxide.
[1 mark]
Show mark scheme
- (a) 64 + 16 = 80
- (b) 64 g
Describe — 2 marks
Iron is extracted from iron(III) oxide in a blast furnace. The iron(III) oxide is heated with carbon, which removes the oxygen from the ore. Aluminium is extracted using a different method.
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(a) Describe what happens to the iron(III) oxide during the extraction process.
[1 mark]
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(b) Describe why aluminium cannot be extracted from aluminium oxide using carbon.
[1 mark]
Show mark scheme
- (a) oxygen is removed (from the iron oxide)
- (a) it is reduced
- (a) iron is produced
- (b) aluminium is more reactive than carbon
- (b) aluminium is above carbon in the reactivity series
Evaluate — 3 marks
A metal extraction company needs to choose between two methods for extracting metals from their ores. Method A uses electrolysis and requires large amounts of electricity. Method B uses carbon reduction in a blast furnace. Both methods produce the pure metal required, but the company wants to minimise costs and environmental impact.
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(a) Explain why Method A (electrolysis) is used for some metals but Method B (carbon reduction) can be used for others.
[1 mark]
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(b) Evaluate which method would be more suitable for a company wanting to reduce both energy costs and carbon emissions. Give a reason for your answer.
[2 marks]
Show mark scheme
- (a) Method A/electrolysis is used for more reactive metals (above carbon in reactivity series)
- (b) Method B/carbon reduction is more suitable
- (b) Method B uses less energy/electricity OR produces lower carbon emissions OR electrolysis is very expensive due to high energy costs
Show — 4 marks
A student investigates the reactions of four metals with dilute hydrochloric acid. The metals are magnesium, zinc, iron, and copper. In a separate investigation, the student researches how different metals are extracted from their ores. The table below shows the observations from the acid reactions.
| Metal | Observation with dilute HCl |
|-------|----------------------------|
| Magnesium | Vigorous fizzing, metal disappears rapidly |
| Zinc | Steady fizzing, metal disappears slowly |
| Iron | Slow fizzing, metal disappears very slowly |
| Copper | No reaction observed |
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(a) Show how the observations in the table support the following order of reactivity, starting with the most reactive: magnesium, zinc, iron, copper.
[2 marks]
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(b) Iron can be extracted from iron oxide by heating with carbon. Magnesium cannot be extracted from magnesium oxide by heating with carbon. Use the reactivity series to show why different extraction methods are needed for these two metals.
[2 marks]
Show mark scheme
- (a) more reactive metals react faster/more vigorously with acid
- (a) magnesium reacts most vigorously (most reactive)
- (a) copper does not react (least reactive)
- (b) carbon is more reactive than iron / can displace iron from its oxide
- (b) carbon is less reactive than magnesium / cannot displace magnesium from its oxide
- (b) more reactive metals require electrolysis for extraction
Define — 4 marks
A mining company extracts copper from copper oxide ore by heating it with carbon in a furnace. The reaction produces copper metal and carbon dioxide. A chemistry student is investigating why carbon can be used to extract copper but cannot be used to extract more reactive metals such as aluminium.
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(a) Define reduction in terms of oxygen.
[1 mark]
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(b) Define the term reactivity series and explain why carbon can be used to extract copper but not aluminium from their metal oxides.
[3 marks]
Show mark scheme
- (a) loss of oxygen
- (b) an ordered list of metals (arranged by reactivity)
- (b) carbon is more reactive than copper / carbon is above copper in the reactivity series
- (b) carbon is less reactive than aluminium / carbon is below aluminium in the reactivity series
GCSE Perfect
/ Chemistry