CIE iGCSE Co-Ordinated Science C9.6 Extraction of metals Exam Style Questions Paper 1
▶️ Answer/Explanation
Aluminium is extracted from bauxite (its ore), not hematite — hematite is the ore of iron; bauxite contains aluminium oxide (\(\text{Al}_2\text{O}_3\)).
Because aluminium is above carbon in the reactivity series, carbon cannot reduce it, so electrolysis of molten aluminium oxide is used instead.
✅ Answer: (B)
Because aluminium is above carbon in the reactivity series, carbon cannot reduce it, so electrolysis of molten aluminium oxide is used instead.
✅ Answer: (B)
▶️ Answer/Explanation
In the blast furnace, carbon (as coke) burns to form carbon monoxide.
Carbon monoxide then removes oxygen from iron(III) oxide: \(\text{Fe}_2\text{O}_3 + 3\text{CO} \rightarrow 2\text{Fe} + 3\text{CO}_2\).
This is a reduction reaction (loss of oxygen from the iron compound), using carbon/carbon monoxide as the reducing agent.
✅ Answer: (D)
Carbon monoxide then removes oxygen from iron(III) oxide: \(\text{Fe}_2\text{O}_3 + 3\text{CO} \rightarrow 2\text{Fe} + 3\text{CO}_2\).
This is a reduction reaction (loss of oxygen from the iron compound), using carbon/carbon monoxide as the reducing agent.
✅ Answer: (D)
▶️ Answer/Explanation
Heating (thermally decomposing) limestone produces lime (calcium oxide): \(\text{CaCO}_3 \rightarrow \text{CaO} + \text{CO}_2\), so statement 3 is correct.
Lime is alkaline and is used to neutralise acidic industrial waste, so statement 4 is also correct.
Limestone/lime is used to increase (not decrease) soil pH, and is not itself classed as a fertilizer, ruling out statements 1 and 2.
✅ Answer: (D)
Lime is alkaline and is used to neutralise acidic industrial waste, so statement 4 is also correct.
Limestone/lime is used to increase (not decrease) soil pH, and is not itself classed as a fertilizer, ruling out statements 1 and 2.
✅ Answer: (D)
▶️ Answer/Explanation
Metals high in the reactivity series, such as aluminium, form very stable compounds that cannot be reduced by carbon.
These metals must instead be extracted by electrolysis of their molten ore, which requires large amounts of electrical energy.
Iron is extracted by reduction with carbon, copper can be extracted by reduction or other methods, and gold is unreactive enough to be found native, so aluminium is the one extracted by electrolysis.
✅ Answer: (A)
These metals must instead be extracted by electrolysis of their molten ore, which requires large amounts of electrical energy.
Iron is extracted by reduction with carbon, copper can be extracted by reduction or other methods, and gold is unreactive enough to be found native, so aluminium is the one extracted by electrolysis.
✅ Answer: (A)
▶️ Answer/Explanation
The limewater turning cloudy confirms carbon dioxide gas is produced, showing carbon has removed oxygen from the metal oxide.
Loss of oxygen from a compound is defined as reduction.
The metal oxide is therefore reduced to the free metal while the carbon is oxidised to carbon dioxide.
✅ Answer: (D)
Loss of oxygen from a compound is defined as reduction.
The metal oxide is therefore reduced to the free metal while the carbon is oxidised to carbon dioxide.
✅ Answer: (D)