Extraction of metals & reduction

Metals are found in the Earth’s crust as the metal itself or as a metal compound.

Why is gold found in the Earth as the metal itself?

Aluminium is extracted from aluminium oxide by electrolysis.

The electrolyte is a molten mixture of aluminium oxide and cryolite.

Aluminium cannot be extracted from aluminium oxide using carbon.

Give one reason why.

Give two reasons why large amounts of energy are needed for the electrolysis of aluminium oxide.

Recycling aluminium needs less energy than extracting new aluminium.

Table 4 shows the energy needed for 1 kg of aluminium to be:

extracted

recycled.

Calculate the percentage decrease in energy needed when aluminium is recycled instead of extracted.

Give your answer to 2 significant figures.

Metals are found in the Earth’s crust as the metal itself or as a metal compound.

Why is gold found in the Earth as the metal itself?

Aluminium is extracted from aluminium oxide by electrolysis.

The electrolyte is a molten mixture of aluminium oxide and cryolite.

Aluminium cannot be extracted from aluminium oxide using carbon.

Give one reason why.

Give two reasons why large amounts of energy are needed for the electrolysis of aluminium oxide.

Recycling aluminium needs less energy than extracting new aluminium.

Table 1 shows the energy needed for 1 kg of aluminium to be:

extracted

recycled.

Calculate the percentage decrease in energy needed when aluminium is recycled instead of extracted.

Give your answer to 2 significant figures.

This question is about metal extraction and recycling.

Most metals are found in the Earth as metal compounds.

Why is gold found in the Earth as the metal itself?

How is aluminium extracted from aluminium compounds?

Tick (✓) one box.

By displacement

By electrolysis

By reduction with carbon

Iron is extracted from iron oxide.

An oxide ion is an oxygen atom that has gained two electrons.

What is the formula of an oxide ion?

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O₂ O²⁻ O²⁺

Iron oxide is heated with carbon to produce iron and carbon dioxide.

The word equation for the reaction is:

Which substance is oxidised in the reaction?

Iron is used to make steel.

Scrap steel can be recycled.

Give two environmental advantages of recycling scrap steel instead of making new steel from iron.

Table 3 shows information about scrap steel in one year.

Calculate the percentage (%) of scrap steel that was recycled in one year.

Figure 5 shows metal food and drink cans.

The metal cans are made from steel or aluminium.

Which property of steel means that steel can be separated from aluminium at a recycling centre?

This question is about metals reacting with oxygen.

Calcium (Ca) reacts with oxygen (O₂) to produce calcium oxide (CaO).

Balance the equation for the reaction.

______ Ca + O₂ → 2 CaO

40 g of calcium reacts completely with oxygen to produce 56 g of calcium oxide.

Calculate the maximum mass of calcium oxide that could be produced from 10 g of calcium.

A student reacted different masses of magnesium with oxygen and measured the mass of magnesium oxide produced.

Figure 3 shows the results.

Why did the student ignore one of the points when drawing the line of best fit on Figure 3 ?

Predict the mass of magnesium oxide produced from 0.5 g of magnesium.

You should extend the line of best fit on Figure 3.

A different student reacted copper with oxygen and measured the mass of copper oxide produced.

The student did repeat measurements for each mass of copper.

Table 1 shows the results when 0.42 g of copper was reacted.

Calculate mean value X in Table 1.

The reaction between copper and oxygen is exothermic.

Which reaction profile represents this reaction?

Tick (✓) one box.

This question is about chemical processes.

Iron can be extracted from iron oxide using carbon.

The word equation for the reaction is:

iron oxide + carbon → iron + carbon dioxide

Why can iron be extracted from iron oxide using carbon?

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Iron is less reactive than carbon.

Iron has the same reactivity as carbon.

Iron is more reactive than carbon.

Which reactant is reduced?

Tick (✓) one box.

Carbon

Carbon dioxide

Iron

Iron oxide

Aluminium is manufactured by the electrolysis of a molten mixture of aluminium oxide and cryolite.

Figure 4 shows the apparatus.

What are the positive electrodes in Figure 4 made of?

Tick (✓) one box.

Aluminium

Carbon

Copper

Iron

Large amounts of energy are used in the extraction of aluminium from aluminium oxide.

Give two reasons why.

Electrolysis is only possible when an ionic compound is molten or in aqueous solution.

Explain why.

You should refer to ions and charge in your answer.

An aqueous solution of copper chloride is electrolysed using inert electrodes.

What is meant by ‘inert’?

Table 2 shows information about the products of the electrolysis of an aqueous solution of copper chloride.

Complete Table 2.

This question is about the extraction of metals.

Name the process that uses bacteria to extract metals.

Iron can be extracted from iron oxide using carbon.

The word equation for the reaction is:

iron oxide + carbon → iron + carbon dioxide

Explain why this reaction is both oxidation and reduction.

Give one reason why some metals cannot be extracted from their oxides using carbon.

Aluminium is manufactured by the electrolysis of a molten mixture of aluminium oxide and cryolite.

Explain why cryolite is used.

Aluminium is produced at the negative electrode.

Complete the half equation for the reaction.

You should balance the equation.

Al³⁺ + ____________ → ____________

This question is about substances found in the Earth’s crust.

Aluminium silicate is a compound found in the Earth’s crust.

The formula of aluminium silicate is Al₂SiO₅

What is the total number of atoms in the formula Al₂SiO₅?

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3 5 7 8

Table 2 shows the percentage of some elements found in the Earth’s crust.

Calculate the simplest whole number ratio for the percentage of silicon to the percentage of aluminium in the Earth’s crust.

Simplest whole number ratio for: percentage of silicon: percentage of aluminium = _____________: _____________

Iron is found as iron oxide in the Earth’s crust.

Iron can be extracted by heating iron oxide with carbon.

Why is iron oxide reacted with carbon to extract iron?

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Iron is less reactive than carbon.

Iron has the same reactivity as carbon.

Iron is more reactive than carbon.

The word equation for the reaction to extract iron is:

iron oxide + carbon iron + carbon dioxide

Which reactant is reduced?

Tick (✓) one box.

Carbon

Carbon dioxide

Iron

Iron oxide

The symbol equation for the reaction to extract iron is:

What is the value of X ?

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2 3 4 5

Aluminium is found as aluminium oxide in the Earth’s crust.

Figure 8 shows the apparatus used for the process to extract aluminium from aluminium oxide.

Name the process used to extract aluminium from aluminium oxide.

What are the positive electrodes made of in this process?

Tick (✓) one box.

Aluminium

Carbon

Copper

Cryolite

Large amounts of energy are used in the process in Figure 8.

Give two ways energy is used in the process.

Diamond and silicon dioxide are also found in the Earth’s crust.

Figure 9 represents the structure of diamond and the structure of silicon dioxide.

Compare the structure and bonding of diamond with the structure and bonding of silicon dioxide.

This question is about magnesium oxide.

What type of substance is magnesium oxide?

Tick (✓) one box.

Compound

Element

Mixture

Magnesium reacts with oxygen to produce magnesium oxide.

Balance the equation for the reaction.

What does the state symbol ‘(s)’ represent?

A student reacted magnesium with oxygen.

Figure 9 shows the apparatus used.

Figure 9

This is the method used.

1. Measure the mass of the empty crucible and lid.

2. Put magnesium into the crucible.

3. Measure the mass of the crucible, lid and magnesium.

4. Heat the crucible strongly.

5. Lift the lid occasionally.

6. Heat until the magnesium stops glowing.

7. Measure the mass of the crucible, lid and magnesium oxide.

Give one safety precaution the student should use.

The magnesium reacted with oxygen.

Suggest where the oxygen comes from.

The student lifted the lid several times.

Why did lifting the lid allow the magnesium to react completely?

Table 3 shows the results.

Calculate the mass of magnesium put into the crucible.

Use Table 3.

Calculate the mass of oxygen that reacted with the magnesium.

Use Table 3.

This question is about iron and steel.

Figure 18 shows a flow chart for the production of iron and steel from iron ore.

Iron ore consists mainly of iron oxide.

In the blast furnace iron oxide reacts with carbon monoxide to form iron and carbon dioxide.

Complete the equation for the reaction between iron oxide and carbon monoxide.

You should balance the equation.

Iron oxide is reduced in the reaction with carbon monoxide.

What does ‘reduced’ mean in this reaction?

Cast iron is an alloy.

Cast iron contains carbon.

Figure 19 shows the arrangement of atoms in pure iron and in cast iron.

Explain why cast iron is harder than pure iron.

In addition to cast iron, scrap steel is added to the steel-making furnace.

Give three environmental advantages of recycling scrap steel in this way.

This question is about iron and steel.

Figure 4 shows a flow chart for the production of iron and steel from iron ore.

Iron ore consists mainly of iron oxide.

In the blast furnace iron oxide reacts with carbon monoxide to form iron and carbon dioxide.

Complete the equation for the reaction between iron oxide and carbon monoxide.

You should balance the equation.

Iron oxide is reduced in the reaction with carbon monoxide.

What does ‘reduced’ mean in this reaction?

Cast iron is an alloy.

Cast iron contains carbon.

Figure 5 shows the arrangement of atoms in pure iron and in cast iron.

Explain why cast iron is harder than pure iron.

In addition to cast iron, scrap steel is added to the steel-making furnace.

Give three environmental advantages of recycling scrap steel in this way.

A teacher extracted copper from copper oxide.

This is the method used.

1. Mix 1.30 g of zinc and 1.59 g of copper oxide.

2. Heat the mixture strongly.

3. When the mixture starts to glow, stop heating.

4. Let the glow spread through the mixture.

5. Leave the mixture to cool.

This reaction is exothermic.

Which part of the method shows the reaction is exothermic?

Tick one box.

The equation for the reaction between zinc and copper oxide is:

1.30 g of zinc fully reacted with 1.59 g of copper oxide to produce 1.62 g of zinc oxide.

What mass of copper was produced?

What is the physical state of zinc oxide in the reaction?

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Which substance has been oxidised in the reaction?

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What type of reaction takes place when zinc reacts with copper oxide?

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Copper is a metal.

Which structure represents the arrangement of atoms in pure copper?

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Copper is used in electrical wiring.

Give one reason why.

In the UK, 40% of the copper we use is recycled copper.

The other 60% is copper obtained by mining.

What is the simplest ratio of recycled copper to copper obtained by mining?

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What are two advantages of recycling copper?

Tick two boxes.