A metal ore is a rock that contains enough of a metal to make it worthwhile extracting.

Why are most metals found as ores rather than as pure elements?

Most metals are found as ores because they are chemically combined with other substances in the Earth's crust. Only very unreactive metals, such as gold and platinum, are found as the uncombined element .

True or False? Gold and platinum are usually found as ores in the Earth's crust.

False. Gold and platinum are unreactive metals. Because they do not easily combine with other substances, they are found as the uncombined element and can be mined directly from the Earth's crust.

Haematite is the common ore of iron. It is an iron oxide (Fe 2 O 3 ) found in the Earth's crust.

Many metal ores are .......... of the metal. This means that extracting the metal from its ore is a .......... process, as oxygen is being removed.

Many metal ores are oxides of the metal. This means that extracting the metal from its ore is a reduction process, as oxygen is being removed.

Bauxite is the main ore of aluminium. It contains aluminium oxide, Al 2 O 3 .

What are the three main methods used to extract metals from their ores?

The three main methods used to extract metals from their ores are: Electrolysis Reduction in a blast furnace Reaction with a more reactive metal

True or False? The extraction of a metal from an oxide ore always involves reduction.

True. When a metal is extracted from an oxide ore, oxygen is removed from the metal compound. Removing oxygen is the definition of reduction , so the process is always a reduction reaction.

Why must metals above carbon in the reactivity series be extracted by electrolysis?

Metals above carbon in the reactivity series cannot be extracted by reduction because they are too reactive to be reduced by carbon. Instead, electrolysis must be used, which requires large amounts of electricity and is therefore an expensive process.

In a blast furnace, .......... is used as the reducing agent to extract iron from its ore, .......... .

In a blast furnace, carbon monoxide is used as the reducing agent to extract iron from its ore, haematite .

What happens in Zone 1 of the blast furnace?

In Zone 1 of the blast furnace, coke (carbon) burns in the hot air blown in at the bottom, producing carbon dioxide . This reaction is exothermic and releases heat, raising the temperature inside the furnace.

True or False? In the blast furnace, carbon monoxide reduces iron(III) oxide to produce iron.

True. In Zone 3, carbon monoxide acts as a reducing agent, removing oxygen from iron(III) oxide (Fe 2 O 3 ) to form molten iron , which collects at the bottom of the furnace.

Slag is the waste product removed from a blast furnace. It forms when calcium oxide (from limestone) reacts with silicon dioxide impurities in the ore, producing calcium silicate, which floats on top of the molten iron.

Why is limestone added to the blast furnace?

Limestone is added to the blast furnace to remove acidic impurities (mainly silicon dioxide) from the iron ore. It thermally decomposes to form calcium oxide , which then reacts with the silicon dioxide to form slag, which is tapped off separately.

Complete the table to show what happens in each zone of the blast furnace. Zone What happens Zone 1 Zone 2 Zone 3

Zone What happens Zone 1 Coke burns in hot air to form carbon dioxide; the furnace is heated Zone 2 Carbon dioxide reacts with more coke to form carbon monoxide Zone 3 Carbon monoxide reduces iron(III) oxide to form molten iron

What is cryolite used for in the extraction of aluminium?

Cryolite is a substance in which aluminium oxide is dissolved before electrolysis. This lowers the melting point of the mixture, making the process less energy-intensive and more economical.

True or False? Aluminium oxide is dissolved in molten cryolite to lower its melting point before electrolysis.

True. Aluminium oxide has a melting point above 2000°C, which would make direct electrolysis very expensive. Dissolving it in molten cryolite gives a mixture with a much lower melting point , reducing energy costs.

Why do the graphite anodes in the aluminium electrolysis cell need to be replaced regularly?

The graphite anodes need to be replaced regularly because oxygen produced at the anode reacts with the graphite (carbon) to form carbon dioxide. This causes the anodes to gradually wear away.

Complete the table to show why aluminium is used in each application. Use Property Aircraft bodies Saucepans Overhead electrical cables Food cans

Use Property Aircraft bodies High strength-to-weight ratio (low density) Saucepans Very good conductor of heat and unreactive Overhead electrical cables Very good conductor of electricity Food cans Non-toxic, resistant to corrosion and resistant to acidic foodstuffs

Why is aluminium used for aircraft bodies rather than a denser metal like iron?

Aluminium is used for aircraft bodies because it has a high strength-to-weight ratio — it is strong enough to withstand the forces involved, but its low density means the aircraft is not too heavy to fly.

True or False? Copper is used for electrical wiring because it is a good conductor of electricity and is ductile.

True. Copper is an excellent conductor of electricity , allowing current to flow easily. It is also ductile , meaning it can be drawn into long thin wires without breaking.

What properties of iron make it useful as a building material?

Iron is useful as a building material because it has good strength , is malleable and ductile so it can be shaped, and is relatively inexpensive compared to other metals.

Mild steel is a type of steel made from iron alloyed with about 0.25% carbon. It is soft and malleable , making it useful for car body panels and wiring.

Copper is used for water pipes because it is .......... , does not react with water, and is .......... enough to be bent into shape.

Copper is used for water pipes because it is non-toxic , does not react with water, and is malleable enough to be bent into shape.

Why is stainless steel used for cutlery and sinks?

Stainless steel is used for cutlery and sinks because it is strong and highly resistant to corrosion . It is made from iron alloyed with around 20% chromium and 10% nickel.

True or False? Stainless steel is resistant to corrosion because it contains chromium and nickel.

True. Stainless steel is an alloy of iron with around 20% chromium and 10% nickel . These additions make it highly resistant to corrosion, which is why it is used for cutlery, sinks and chemical plants.

A ductile material is one that can be drawn out into thin wires without breaking.

An alloy is a mixture of two or more metals, or a metal mixed with a non-metal such as carbon . Alloys often have different properties from the pure metals they contain.

Why are alloys harder than the pure metals they are made from?

Alloys are harder than pure metals because they contain atoms of different sizes . These distort the regular arrangement of atoms in the metal, making it more difficult for the layers to slide over each other .

True or False? Pure iron is harder than steel because it contains no other elements.

False. Pure iron has a regular arrangement of atoms, which allows layers to slide easily. Steel is an alloy in which atoms of different sizes distort this arrangement, making it harder than pure iron.

Brass is an alloy made from .......... (70%) and .......... (30%).

Brass is an alloy made from copper (70%) and zinc (30%).

What properties can alloys have that make them more useful than pure metals?

Alloys can be stronger and harder than the pure metals they contain. They can also be more resistant to corrosion and to extreme temperatures.

True or False? Steel is an alloy of iron and carbon.

True. Steel is made by alloying iron with carbon . The carbon atoms are a different size to the iron atoms, distorting the lattice and making the alloy harder than pure iron.

Steel is an alloy of iron and carbon . It is stronger and harder than pure iron, making it more useful as a structural and engineering material.

IGCSEChemistryEdexcelChemistry (Modular)Unit 1Flashcards2. Inorganic Chemistry: Part 1Extraction & uses of metals

Extraction & uses of metals (Edexcel IGCSE Chemistry (Modular): Unit 1): Flashcards

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Cards in this collection (34)

Define metal ore.
A metal ore is a rock that contains enough of a metal to make it worthwhile extracting.
Why are most metals found as ores rather than as pure elements?
Most metals are found as ores because they are chemically combined with other substances in the Earth's crust.
Only very unreactive metals, such as gold and platinum, are found as the uncombined element.
True or False?
Gold and platinum are usually found as ores in the Earth's crust.
False.
Gold and platinum are unreactive metals. Because they do not easily combine with other substances, they are found as the uncombined element and can be mined directly from the Earth's crust.
What is haematite?
Haematite is the common ore of iron. It is an iron oxide (Fe₂O₃) found in the Earth's crust.
Many metal ores are .......... of the metal. This means that extracting the metal from its ore is a .......... process, as oxygen is being removed.
Many metal ores are oxides of the metal. This means that extracting the metal from its ore is a reduction process, as oxygen is being removed.
What is bauxite?
Bauxite is the main ore of aluminium. It contains aluminium oxide, Al₂O₃.
What are the three main methods used to extract metals from their ores?
The three main methods used to extract metals from their ores are:
1. Electrolysis
2. Reduction in a blast furnace
3. Reaction with a more reactive metal
True or False?
The extraction of a metal from an oxide ore always involves reduction.
True.
When a metal is extracted from an oxide ore, oxygen is removed from the metal compound. Removing oxygen is the definition of reduction, so the process is always a reduction reaction.
Why must metals above carbon in the reactivity series be extracted by electrolysis?
Metals above carbon in the reactivity series cannot be extracted by reduction because they are too reactive to be reduced by carbon.
Instead, electrolysis must be used, which requires large amounts of electricity and is therefore an expensive process.
In a blast furnace, .......... is used as the reducing agent to extract iron from its ore, .......... .
In a blast furnace, carbon monoxide is used as the reducing agent to extract iron from its ore, haematite.
What happens in Zone 1 of the blast furnace?
In Zone 1 of the blast furnace, coke (carbon) burns in the hot air blown in at the bottom, producing carbon dioxide.
This reaction is exothermic and releases heat, raising the temperature inside the furnace.
True or False?
In the blast furnace, carbon monoxide reduces iron(III) oxide to produce iron.
True.
In Zone 3, carbon monoxide acts as a reducing agent, removing oxygen from iron(III) oxide (Fe₂O₃) to form molten iron, which collects at the bottom of the furnace.
Define slag.
Slag is the waste product removed from a blast furnace. It forms when calcium oxide (from limestone) reacts with silicon dioxide impurities in the ore, producing calcium silicate, which floats on top of the molten iron.
Why is limestone added to the blast furnace?
Limestone is added to the blast furnace to remove acidic impurities (mainly silicon dioxide) from the iron ore.
It thermally decomposes to form calcium oxide, which then reacts with the silicon dioxide to form slag, which is tapped off separately.

Complete the table to show what happens in each zone of the blast furnace.

Zone	What happens
Zone 1
Zone 2
Zone 3

Zone	What happens
Zone 1	Coke burns in hot air to form carbon dioxide; the furnace is heated
Zone 2	Carbon dioxide reacts with more coke to form carbon monoxide
Zone 3	Carbon monoxide reduces iron(III) oxide to form molten iron

What is cryolite used for in the extraction of aluminium?
Cryolite is a substance in which aluminium oxide is dissolved before electrolysis. This lowers the melting point of the mixture, making the process less energy-intensive and more economical.
True or False?
Aluminium oxide is dissolved in molten cryolite to lower its melting point before electrolysis.
True.
Aluminium oxide has a melting point above 2000°C, which would make direct electrolysis very expensive. Dissolving it in molten cryolite gives a mixture with a much lower melting point, reducing energy costs.
Why do the graphite anodes in the aluminium electrolysis cell need to be replaced regularly?
The graphite anodes need to be replaced regularly because oxygen produced at the anode reacts with the graphite (carbon) to form carbon dioxide.
This causes the anodes to gradually wear away.

Complete the table to show why aluminium is used in each application.

Use	Property
Aircraft bodies
Saucepans
Overhead electrical cables
Food cans

Use	Property
Aircraft bodies	High strength-to-weight ratio (low density)
Saucepans	Very good conductor of heat and unreactive
Overhead electrical cables	Very good conductor of electricity
Food cans	Non-toxic, resistant to corrosion and resistant to acidic foodstuffs

Why is aluminium used for aircraft bodies rather than a denser metal like iron?
Aluminium is used for aircraft bodies because it has a high strength-to-weight ratio — it is strong enough to withstand the forces involved, but its low density means the aircraft is not too heavy to fly.
True or False?
Copper is used for electrical wiring because it is a good conductor of electricity and is ductile.
True.
Copper is an excellent conductor of electricity, allowing current to flow easily. It is also ductile, meaning it can be drawn into long thin wires without breaking.
What properties of iron make it useful as a building material?
Iron is useful as a building material because it has good strength, is malleable and ductile so it can be shaped, and is relatively inexpensive compared to other metals.
What is mild steel?
Mild steel is a type of steel made from iron alloyed with about 0.25% carbon. It is soft and malleable, making it useful for car body panels and wiring.
Copper is used for water pipes because it is .......... , does not react with water, and is .......... enough to be bent into shape.
Copper is used for water pipes because it is non-toxic, does not react with water, and is malleable enough to be bent into shape.
Why is stainless steel used for cutlery and sinks?
Stainless steel is used for cutlery and sinks because it is strong and highly resistant to corrosion. It is made from iron alloyed with around 20% chromium and 10% nickel.
True or False?
Stainless steel is resistant to corrosion because it contains chromium and nickel.
True.
Stainless steel is an alloy of iron with around 20% chromium and 10% nickel. These additions make it highly resistant to corrosion, which is why it is used for cutlery, sinks and chemical plants.
What is ductile?
A ductile material is one that can be drawn out into thin wires without breaking.
Define alloy.
An alloy is a mixture of two or more metals, or a metal mixed with a non-metal such as carbon. Alloys often have different properties from the pure metals they contain.
Why are alloys harder than the pure metals they are made from?
Alloys are harder than pure metals because they contain atoms of different sizes. These distort the regular arrangement of atoms in the metal, making it more difficult for the layers to slide over each other.
True or False?
Pure iron is harder than steel because it contains no other elements.
False.
Pure iron has a regular arrangement of atoms, which allows layers to slide easily. Steel is an alloy in which atoms of different sizes distort this arrangement, making it harder than pure iron.
Brass is an alloy made from .......... (70%) and .......... (30%).
Brass is an alloy made from copper (70%) and zinc (30%).
What properties can alloys have that make them more useful than pure metals?
Alloys can be stronger and harder than the pure metals they contain. They can also be more resistant to corrosion and to extreme temperatures.
True or False?
Steel is an alloy of iron and carbon.
True.
Steel is made by alloying iron with carbon. The carbon atoms are a different size to the iron atoms, distorting the lattice and making the alloy harder than pure iron.
What is steel?
Steel is an alloy of iron and carbon. It is stronger and harder than pure iron, making it more useful as a structural and engineering material.

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