Extraction of metals and reduction

This question is about metals.

Complete the sentence.

Choose the answer from the box.

Iron is extracted from iron oxide by reduction with carbon.

Why is iron extracted by reduction with carbon?

Tick () one box.

Aluminium is extracted by the electrolysis of aluminium oxide.

Figure 8 shows the apparatus used to extract aluminium.

The mixture of aluminium oxide and cryolite has a lower melting point than aluminium oxide alone.

Why is the melting point lowered?

Tick () one box.

After some time, the positive electrodes need to be replaced.

Why must the positive electrodes be replaced?

Tick () one box.

Aluminium can be mixed with other metals to form alloys.

How does the hardness of an alloy of aluminium compare with the hardness of pure aluminium?

Tick () one box.

Aluminium can form an alloy with silver.

Figure 9 shows how the melting point of the alloy changes with the percentage (%) of silver in the mixture.

Describe how the melting point of the alloy changes as the percentage of silver in the mixture increases.

Use data from Figure 9.

This question is about metals.

Iron is extracted from iron oxide by reduction with carbon.

Why can iron be extracted by reduction with carbon?

Answer in terms of reactivity.

Aluminium is extracted by the electrolysis of aluminium oxide.

Figure 4 shows the apparatus used to extract aluminium.

Explain why a mixture of aluminium oxide and cryolite is used as the electrolyte instead of only aluminium oxide.

Oxygen gas is produced at the positive electrode.

Write a balanced half equation for the production of oxygen at the positive electrode.

Chromium is extracted by reacting chromium oxide with aluminium.

The equation for the reaction is:

Which substance in the equation is reduced?

Table 3 shows the relative cost of extracting equal masses of aluminium, chromium and iron.

Give one reason for the difference in the cost of extracting aluminium and iron.

Use Table 3.

Give one reason for the difference in the cost of extracting aluminium and chromium

Use Table 3.

Metals are mixed together to form alloys.

Explain why alloys are harder than pure metals.

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.

This question is about extraction of metals.

Aluminium is extracted from a molten mixture of aluminium oxide and cryolite using electrolysis. Figure 12 shows the electrolysis cell.

Complete the sentence.

The extraction of aluminium is expensive because the process uses

Oxygen is produced at the positive carbon electrodes. The oxygen reacts with the carbon electrodes. Which gas is produced when oxygen reacts with the positive carbon electrodes?

Titanium is extracted from titanium chloride by reacting titanium chloride with sodium.

The reaction between titanium chloride and sodium is carried out in an

Suggest why the reaction is carried out in an inert atmosphere.

Complete the sentence. Choose the answer from the box.

Balance the equation for the reaction.

Copper is extracted from copper oxide by reacting copper oxide with carbon.

Figure 13 shows the apparatus.

The equation for the reaction is:

In an experiment 15.9 g of copper oxide and 1.2 g of carbon reacted. 12.7 g of copper was produced in the reaction.

Calculate the mass of carbon dioxide produced in this experiment.

Explain why the mass of the contents in the crucible changed during the experiment.

What happens to copper oxide in the reaction? Give one reason for your answer. Use the equation for the reaction. Tick (✓) one box.

This question is about elements and compounds.

Magnesium and oxygen react to produce magnesium oxide. Balance the equation for the reaction.

Suggest one safety precaution that should be taken when heating magnesium and oxygen.

Calculate the relative formula mass (M_r) of magnesium fluoride (MgF₂). Relative atomic masses (A_r): F = 19 Mg = 24

Argon is a noble gas. Explain why no product is formed when magnesium and argon are heated together.

Figure 10 shows a reactivity series.

Figure 10

Draw one line from each metal to the method used to extract that metal. Use Figure 10.

Metal Method used to extract that metal

A substance conducts electricity when it has charged particles that are free to move.

Figure 11 represents the structure of sodium chloride.

Explain why sodium chloride conducts electricity when molten but not when solid.

Figure 12 represents the structure of sodium metal.

Explain why sodium metal conducts electricity when solid.

This question is about elements and compounds.

Figure 8 shows a reactivity series.

Figure 8

Give the method and conditions used to extract metal Y from a compound of metal Y

Sodium reacts with titanium chloride (TiCl₄) to produce titanium.

Complete the equation. You should balance the equation.

The reaction between sodium and titanium chloride is a redox reaction. Write a half-equation to show that sodium is oxidised in this reaction.

108 g of aluminum reacts with 1.21 kg of copper chloride to produce copper. The equation for the reaction is:

Calculate the maximum mass of copper produced in grams (g). You should determine the limiting reactant. Relative atomic masses (A_r): Al = 27 Cu = 63.5 Relative formula masses (M_r): CuCl₂ = 134.5 AlCl₃ = 133.5

Limiting reactant is Mass of copper = g

Sodium metal and sodium chloride are both able to conduct electricity.

Describe how sodium metal conducts electricity.

Explain how sodium chloride can 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