An ore is a naturally occurring rock or mineral from which a metal can be extracted profitably.

Metals found naturally as uncombined elements, such as gold and platinum, are described as ______ metals.

Metals found naturally as uncombined elements, such as gold and platinum, are described as native metals.

How does the position of a metal in the reactivity series determine the method used to extract it?

Metals below carbon in the reactivity series can be extracted by reduction with carbon or carbon monoxide. Metals above carbon are too reactive for carbon to reduce and must be extracted by electrolysis.

Metals above carbon in the reactivity series cannot be extracted by carbon reduction, so they are extracted by ______ .

Metals above carbon in the reactivity series cannot be extracted by carbon reduction, so they are extracted by electrolysis .

True or False? Carbon can be used to reduce aluminium oxide to obtain aluminium.

False. Aluminium is above carbon in the reactivity series, so carbon cannot reduce aluminium oxide. Aluminium must be extracted by electrolysis.

The more reactive a metal is, the ______ it is to separate it from its ore, and the more energy its extraction requires.

The more reactive a metal is, the harder it is to separate it from its ore, and the more energy its extraction requires.

Give one example of a metal extracted by carbon reduction and state the ore it is extracted from.

Iron is extracted from iron ore (hematite) by reduction with carbon monoxide in the blast furnace.

What is the blast furnace?

The blast furnace is a large industrial furnace used to extract iron from iron ore (hematite) by reduction with carbon monoxide.

In the blast furnace, carbon (coke) burns in hot air to produce ______ , which then reacts with more coke to form carbon monoxide.

In the blast furnace, carbon (coke) burns in hot air to produce carbon dioxide , which then reacts with more coke to form carbon monoxide.

What is the role of carbon monoxide in the blast furnace?

Carbon monoxide acts as the reducing agent, removing oxygen from iron(III) oxide to produce molten iron. The word equation is: iron(III) oxide + carbon monoxide → iron + carbon dioxide.

Limestone is added to the blast furnace to remove silicon dioxide ______ in the iron ore, forming ______ .

Limestone is added to the blast furnace to remove silicon dioxide impurities in the iron ore, forming slag .

True or False? In the blast furnace, carbon monoxide is both produced inside the furnace and used as a reducing agent.

True. Carbon dioxide first reacts with more coke (carbon) to produce carbon monoxide, which then reduces iron(III) oxide to produce molten iron.

Limestone decomposes in the blast furnace to form calcium ______ and carbon dioxide.

Limestone decomposes in the blast furnace to form calcium oxide and carbon dioxide.

Why is limestone added to the blast furnace, and what product does it help form?

Limestone is added to remove silicon dioxide impurities. It decomposes to calcium oxide, which reacts with silicon dioxide to form slag that is tapped off separately.

Bauxite is the ore of aluminium, from which aluminium oxide (Al 2 O 3 ) is purified before being used in electrolysis.

During the extraction of aluminium, aluminium oxide is dissolved in molten ______ to lower its melting point before electrolysis.

During the extraction of aluminium, aluminium oxide is dissolved in molten cryolite to lower its melting point before electrolysis.

Why is cryolite used in the extraction of aluminium, and why does this reduce costs?

Aluminium oxide has a very high melting point. Dissolving it in molten cryolite lowers the temperature at which electrolysis can occur, reducing the energy required and making the process cheaper.

At the cathode during electrolysis of aluminium oxide, aluminium ions are reduced: Al 3+ + 3e - → ______ .

At the cathode during electrolysis of aluminium oxide, aluminium ions are reduced: Al 3+ + 3e - → Al

True or False? The carbon anodes in aluminium extraction must be replaced regularly because they react with the aluminium ions in the electrolyte.

False. The carbon anodes react with the oxygen produced at the anode, forming carbon dioxide and gradually burning away, which is why they must be replaced regularly.

At the anode during electrolysis of aluminium oxide, oxide ions are oxidised: 2O 2- → O 2 + ______ e - .

At the anode during electrolysis of aluminium oxide, oxide ions are oxidised: 2O 2- → O 2 + 4 e -

Give two reasons why the extraction of aluminium by electrolysis is expensive.

Aluminium extraction is expensive because large amounts of electricity are needed to reduce the aluminium ions, and the carbon anodes must be regularly replaced as they burn away in the oxygen produced.

O LevelChemistryCambridge (CIE)Flashcards9. Metals9.6 Extraction of Metals

9.6 Extraction of Metals (Cambridge (CIE) O Level Chemistry): Flashcards

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FrontExtraction of Metals
What is an ore?

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Cards in this collection (21)

What is an ore?
An ore is a naturally occurring rock or mineral from which a metal can be extracted profitably.
Metals found naturally as uncombined elements, such as gold and platinum, are described as ______ metals.
Metals found naturally as uncombined elements, such as gold and platinum, are described as native metals.
How does the position of a metal in the reactivity series determine the method used to extract it?
Metals below carbon in the reactivity series can be extracted by reduction with carbon or carbon monoxide.
Metals above carbon are too reactive for carbon to reduce and must be extracted by electrolysis.
Metals above carbon in the reactivity series cannot be extracted by carbon reduction, so they are extracted by ______.
Metals above carbon in the reactivity series cannot be extracted by carbon reduction, so they are extracted by electrolysis.
True or False?
Carbon can be used to reduce aluminium oxide to obtain aluminium.
False.
Aluminium is above carbon in the reactivity series, so carbon cannot reduce aluminium oxide. Aluminium must be extracted by electrolysis.
The more reactive a metal is, the ______ it is to separate it from its ore, and the more energy its extraction requires.
The more reactive a metal is, the harder it is to separate it from its ore, and the more energy its extraction requires.
Give one example of a metal extracted by carbon reduction and state the ore it is extracted from.
Iron is extracted from iron ore (hematite) by reduction with carbon monoxide in the blast furnace.
What is the blast furnace?
The blast furnace is a large industrial furnace used to extract iron from iron ore (hematite) by reduction with carbon monoxide.
In the blast furnace, carbon (coke) burns in hot air to produce ______, which then reacts with more coke to form carbon monoxide.
In the blast furnace, carbon (coke) burns in hot air to produce carbon dioxide, which then reacts with more coke to form carbon monoxide.
What is the role of carbon monoxide in the blast furnace?
Carbon monoxide acts as the reducing agent, removing oxygen from iron(III) oxide to produce molten iron. The word equation is:
iron(III) oxide + carbon monoxide → iron + carbon dioxide.
Limestone is added to the blast furnace to remove silicon dioxide ______ in the iron ore, forming ______.
Limestone is added to the blast furnace to remove silicon dioxide impurities in the iron ore, forming slag.
True or False?
In the blast furnace, carbon monoxide is both produced inside the furnace and used as a reducing agent.
True.
Carbon dioxide first reacts with more coke (carbon) to produce carbon monoxide, which then reduces iron(III) oxide to produce molten iron.
Limestone decomposes in the blast furnace to form calcium ______ and carbon dioxide.
Limestone decomposes in the blast furnace to form calcium oxide and carbon dioxide.
Why is limestone added to the blast furnace, and what product does it help form?
Limestone is added to remove silicon dioxide impurities. It decomposes to calcium oxide, which reacts with silicon dioxide to form slag that is tapped off separately.
What is bauxite?
Bauxite is the ore of aluminium, from which aluminium oxide (Al₂O₃) is purified before being used in electrolysis.
During the extraction of aluminium, aluminium oxide is dissolved in molten ______ to lower its melting point before electrolysis.
During the extraction of aluminium, aluminium oxide is dissolved in molten cryolite to lower its melting point before electrolysis.
Why is cryolite used in the extraction of aluminium, and why does this reduce costs?
Aluminium oxide has a very high melting point. Dissolving it in molten cryolite lowers the temperature at which electrolysis can occur, reducing the energy required and making the process cheaper.
At the cathode during electrolysis of aluminium oxide, aluminium ions are reduced:
Al³⁺ + 3e^- → ______.
At the cathode during electrolysis of aluminium oxide, aluminium ions are reduced:
Al³⁺ + 3e^- → Al
True or False?
The carbon anodes in aluminium extraction must be replaced regularly because they react with the aluminium ions in the electrolyte.
False.
The carbon anodes react with the oxygen produced at the anode, forming carbon dioxide and gradually burning away, which is why they must be replaced regularly.
At the anode during electrolysis of aluminium oxide, oxide ions are oxidised:
2O^2- → O₂ + ______ e^-.
At the anode during electrolysis of aluminium oxide, oxide ions are oxidised:
2O^2- → O₂ + 4e^-
Give two reasons why the extraction of aluminium by electrolysis is expensive.
Aluminium extraction is expensive because large amounts of electricity are needed to reduce the aluminium ions, and the carbon anodes must be regularly replaced as they burn away in the oxygen produced.

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