Electrolysis

In the Earth most metals are found as compounds.

Name one metal that is found in the Earth as the metal itself.

Figure 9 shows a reactivity series.

Suggest the most economical method for extracting metal Z from an oxide of metal Z

Figure 10 shows the electrolysis cell used to extract aluminium from aluminium oxide.

Name substance X shown in Figure 10.

Explain what happens to the positive carbon electrodes during the extraction of aluminium from aluminium oxide.

The formula of aluminium oxide is Al₂O₃

Write a half equation for the reaction at the negative electrode in Figure 10.

During electrolysis ions are discharged at the electrodes to produce elements. A student investigates the electrolysis of sodium chloride.

Sodium chloride solution conducts electricity. Complete the sentence.

Figure 5 shows the apparatus for the electrolysis of sodium chloride solution.

Suggest an element that could be used to make the inert electrodes.

Complete the half equation for the production of chlorine (Cl₂) at the positive electrode.

Sodium chloride solution has a pH of 7 During the electrolysis of sodium chloride solution:

• hydrogen gas is produced at the negative electrode

• the pH of the solution increases.

Explain why.

This question is about electrolysis.

Complete the sentence. Choose the answer from the box.

Copper chloride can conduct electricity when in solution or

Figure 1 shows the apparatus used for the electrolysis of copper chloride solution.

There are four ions in copper chloride solution:

• Cu²⁺

• Cl^–

• H⁺

• OH^–

Why do Cl^– ions and OH^– ions move to the positive electrode?

Where do the H⁺ and OH^– ions come from in the electrolysis of copper chloride solution? Tick (✓) one box.

Which ion produces a metal? Tick (✓) one box.

Figure 2 shows the apparatus during the electrolysis of copper chloride solution.

Describe what is seen at each electrode during the electrolysis of copper chloride solution. Positive electrode

Negative electrode

500 cm³ of copper chloride solution contains 6.50 g of copper chloride. Calculate the mass of copper chloride in 40.0 cm³ of this copper chloride solution.

This question is about elements and compounds.

Figure 5 shows the proportion of elements in the periodic table that are metals and non-metals.

Determine the percentage of the elements in Figure 5 that are metals.

Give two physical properties of metals.

Sodium reacts with chlorine to produce sodium chloride. Balance the equation for the reaction.

Figure 6 shows part of the structure of sodium chloride (NaC l).

What holds the particles together in sodium chloride? Use Figure 6. Tick (✓) one box.

Solid sodium chloride does not conduct electricity. Give two ways in which sodium chloride can be made to conduct electricity.

This question is about the extraction of aluminium.

An aluminium atom is represented as: 27 A l 13 Give the number of electrons and neutrons in the aluminium atom.

Aluminium is extracted by the electrolysis of a molten mixture of aluminium oxide and cryolite. Figure 11 shows the cell used for the electrolysis.

Aluminium is produced by the reduction of aluminium oxide (Al₂O₃). What is meant by the term reduction?

Oxygen is formed at the positive carbon electrodes. Explain why the positive carbon electrodes must be continually replaced.

A substance conducts electricity because of free moving, charged particles. What are the free moving, charged particles in a:

• carbon electrode (made from graphite)

• molten mixture of aluminium oxide and cryolite

• metal wire?

Molten mixture of aluminium oxide and cryolite

This question is about the extraction of aluminium.

An aluminium atom is represented as: 27 A l 13 Give the number of electrons and neutrons in the aluminium atom.

Aluminium is extracted by the electrolysis of a molten mixture of aluminium oxide and cryolite. Figure 1 shows the cell used for the electrolysis.

Aluminium is produced by the reduction of aluminium oxide (Al₂O₃). What is meant by the term reduction?

Oxygen is formed at the positive carbon electrodes. Explain why the positive carbon electrodes must be continually replaced.

A substance conducts electricity because of free moving, charged particles. What are the free moving, charged particles in a:

• carbon electrode (made from graphite)

• molten mixture of aluminium oxide and cryolite

• metal wire?

Molten mixture of aluminium oxide and cryolite

This question is about structure and bonding.

Figure 1 shows part of the structure of calcium oxide (CaO).

What type of bonding is present in calcium oxide?

Tick one box.

02

Figure 2 shows a particle of methane (CH₄).

What type of particle is present in Figure 2 ?

Tick one box.

Figure 3 shows the structure of C₆₀

Complete the sentence. Choose the answer from the box.

Figure 4 shows the structure of graphite.

What type of bond is labelled A in Figure 4 ? Tick one box.

In graphite, each carbon atom forms bonds with other carbon atoms as shown in

Figure 4

How many electrons does one carbon atom use to form one bond? Tick one box.

An electric current is passed through copper. Figure 5 shows the apparatus used.

Complete the sentence. Choose the answer from the box.

Complete the sentence. Choose the answer from the box.

Figure 6 shows the apparatus used to investigate the effect of electricity on sodium chloride solution.

Complete the sentence. Choose the answer from the box.

Sodium chloride is made up of ions. Figure 7 shows the apparatus used to investigate the effect of electricity on solid sodium chloride and molten sodium chloride.

Table 1 shows the results.

Draw one line from each statement to the correct reason.