Using electrolysis to extract metals

This question is about metals and metal compounds.

The method used to extract a metal depends on the reactivity of the metal.

Explain which method is used to extract sodium metal from sodium chloride.

The diagram shows the arrangement of particles in a pure metal.

Explain why pure metals are soft.

The diagram shows the electronic structure of an atom of sodium and an atom of oxygen.

Describe, in terms of electrons, what happens when sodium reacts with oxygen.

The table shows the melting points of sodium and sodium oxide.

Explain why sodium and sodium oxide have different melting points.

In your answer you should refer to:

• the structures of sodium and sodium oxide

• the forces between the particles

Iron metal was discovered several thousand years ago. Iron is produced industrially from iron(III) oxide by extraction using carbon.

Sodium is a metal in Group 1 of the Periodic Table. Sodium was discovered by Sir Humphrey Davy in 1807. It is produced industrially by the electrolysis of sodium chloride.

Explain, using the reactivity series, why carbon can be used to extract iron from iron(III) oxide.

Suggest why sodium was not discovered until 1807.

The diagram shows a simplified version of the Downs cell, which can be used to produce sodium industrially. The electrolyte is molten sodium chloride.

Explain why the molten electrolyte conducts electricity.

What is the formula of the cation in the electrolyte?

During the production of sodium, small explosions can be heard.

Explain why using sodium chloride that is not completely dry could cause these small explosions.

Give ionic half-equations for the reactions at the anode and cathode.

Explain why the reactivity of metals in Group 1 increases from lithium to potassium.

This question is about magnesium and magnesium compounds.

Magnesium burns in oxygen to form magnesium oxide.

State two observations that would be seen during the reaction.

The diagram shows the electron configurations of a magnesium atom and an oxygen atom.

Describe the changes in the electronic configurations when magnesium reacts with oxygen to form the ionic compound magnesium oxide, MgO

Magnesium can be produced by the electrolysis of molten magnesium chloride.

State why magnesium cannot be produced by heating magnesium oxide with carbon.

Explain the different ways that magnesium and magnesium chloride conduct electricity.

magnesium

magnesium chloride

During the electrolysis of molten magnesium chloride, magnesium is formed at the negative electrode.

The ionic half‑equation for the reaction is

State why this is a reduction reaction.

Write an ionic half‑equation for the formation of chlorine at the positive electrode.

Metals are found in the Earth’s crust either as uncombined elements or in metal compounds in rocks.

The method of extraction of a metal is related to its position in the reactivity series.

The table shows the positions of some metals and carbon in the reactivity series.

State the name given to rocks that contain metal compounds used in the extraction of metals.

Name a metal that is found as an uncombined element in the Earth’s crust.

Carbon extraction and electrolysis are two methods of obtaining a metal from a compound.

Explain, without giving practical details, which method is most suitable to obtain calcium from calcium chloride.

Explain, without giving practical details, which method is most suitable to obtain lead from lead oxide.

Explain, using a labelled diagram, why lead metal is malleable.

Aluminium is extracted from aluminium oxide.

The overall equation for the process is

Calculate the maximum mass, in grams, of aluminium that could be obtained from 1.275 kg of aluminium oxide.

This question is about the metal aluminium.

Aluminium is malleable and conducts electricity.

The diagram shows the arrangement of the ions in aluminium metal.

Explain why aluminium is malleable.

Explain why aluminium conducts electricity.

Aluminium cannot be extracted by heating a mixture of carbon and aluminium oxide.

Give a reason why heating a mixture of aluminium oxide and carbon does not produce aluminium.

Aluminium is extracted industrially by the electrolysis of molten aluminium oxide Al₂O₃ at a temperature of about 950 °C.

Aluminium metal forms at the negative electrode and oxygen gas forms at the positive electrode. The positive and negative electrodes are made of graphite.

The diagram shows the apparatus used.

Explain how aluminium metal forms at the negative electrode.

Write an ionic half-equation for the formation of oxygen gas at the positive electrode.

Suggest why carbon dioxide gas is also produced at the positive electrode.

Aluminium reacts with iron(III) oxide. The reaction is exothermic.

The equation for the reaction is

State how the equation shows that iron(III) oxide is reduced.

Draw an energy level diagram for the reaction between aluminium and iron(III) oxide.

This question is about the metal aluminium.

Draw a labelled diagram to represent the structure and bonding in a metal.

Explain why a metal conducts electricity.

Aluminium is used to make cans for drinks.

Give two properties of aluminium that make it suitable for this use.

Aluminium is extracted from aluminium oxide (Al₂O₃) by electrolysis.

The electrolyte is aluminium oxide dissolved in molten cryolite.

State why aluminium cannot be extracted by heating aluminium oxide with carbon.

Aluminium is produced at the negative electrode.

The ionic half-equation for the reaction is

State why this is a reduction reaction.

Complete the ionic half-equation for the reaction at the positive electrode.