Extraction of metals & reduction

This question is about metals and metal oxides.

Tin (Sn) is extracted from tin oxide using carbon.

The equation for the reaction is:

Which substance is reduced in this reaction?

Give one reason for your answer.

Answer in terms of oxygen.

Substance reduced

Why can carbon be used to extract tin from tin oxide?

Cadmium (Cd) can be extracted by the reaction of cadmium oxide with carbon.

The equation for the reaction is:

Calculate the percentage atom economy for the production of cadmium in this reaction.

Relative atomic masses (A_r): C = 12 Cd = 112

Relative formula mass (M_r): CdO = 128

Tungsten is a transition metal.

Potassium is a Group 1 metal.

Give two differences between the properties of tungsten and the properties of potassium.

Tungsten oxide reacts with hydrogen to give tungsten (W) and water.

The equation for the reaction is:

The law of conservation of mass states:

‘The mass of the products equals the mass of the reactants during a chemical reaction.’

Show that the equation obeys the law of conservation of mass.

Relative atomic mass (A_r): W = 184

Relative formula masses (M_r): H₂ = 2 WO₃ = 232 H₂O = 18

The reaction producing tungsten has a high atom economy.

Why is it important to use reactions with a high atom economy in industry?

This question is about metals and metal oxides.

Tin (Sn) is extracted from tin oxide using carbon.

The equation for the reaction is:

Which substance is reduced in this reaction?

Give one reason for your answer.

Answer in terms of oxygen.

Substance reduced

Why can carbon be used to extract tin from tin oxide?

Cadmium (Cd) can be extracted by the reaction of cadmium oxide with carbon.

The equation for the reaction is:

Calculate the percentage atom economy for the production of cadmium in this reaction.

Relative atomic masses (A_r): C = 12 Cd = 112

Relative formula mass (M_r): CdO = 128

Tungsten is a transition metal.

Potassium is a Group 1 metal.

Give two differences between the properties of tungsten and the properties of potassium.

Tungsten oxide reacts with hydrogen to give tungsten (W) and water.

The equation for the reaction is:

The law of conservation of mass states:

‘The mass of the products equals the mass of the reactants during a chemical reaction.’

Show that the equation obeys the law of conservation of mass.

Relative atomic mass (A_r): W = 184

Relative formula masses (M_r): H₂ = 2 WO₃ = 232 H₂O = 18

The reaction producing tungsten has a high atom economy.

Why is it important to use reactions with a high atom economy in industry?

This question is about electrolysis and the extraction of metals.

Why can some molten substances be electrolysed?

Tick () one box.

Table 3 shows the products of the electrolysis of some molten compounds.

Complete Table 3.

Aluminium is extracted by electrolysing molten aluminium oxide.

Balance the equation for the reaction.

Choose numbers from the box.

Calculate the relative formula mass (M_r) of aluminium oxide (Al₂O₃).

Relative atomic masses (A_r): O = 16 Al = 27

Figure 13 shows part of the reactivity series of metals.

The non-metal carbon has been included.

Metals can be extracted from their compounds by:

electrolysis

reduction with carbon.

Electrolysis is more expensive than reduction with carbon.

Predict one metal that would be extracted by each method.

Use Figure 13.

This question is about displacement reactions.

Iron is extracted from iron oxide by a displacement reaction with carbon.

Balance the equation for the reaction.

Iron oxide is reduced in this reaction. How does the equation show that iron oxide is reduced?

Calculate the relative formula mass (M_r) of Fe₂O₃ Relative atomic masses (A_r): O = 16 Fe = 56

Copper oxide reacts with hydrogen to produce copper. The equation for the reaction is:

Calculate the percentage atom economy for obtaining copper from this reaction. Use the equation:

Relative atomic mass (A_r): Cu = 63.5 Relative formula masses (M_r): H₂ = 2 CuO = 79.5

A student investigated the reactivity of four different metals, A, B, C and D. The student:

• added each metal to aqueous solutions of each of the metal sulfates

• observed whether a reaction took place.

Give one observation that would show a reaction took place.

Table 4 shows the results.

shows that a displacement reaction took place. × shows that a displacement reaction did not take place. Write metals A, B, C and D in order of reactivity. Give a reason for your order of reactivity.

This question is about displacement reactions.

Iron is extracted from iron oxide by a displacement reaction with carbon. The equation for the reaction is:

Which substance in the equation is reduced? Give one reason for your answer. Answer in terms of oxygen.

Which expression shows how to calculate the mass of carbon needed to produce 1 mole of iron from iron oxide? Relative atomic mass (A_r): C = 12 Tick (✓) one box.

A student investigated displacement reactions of four different metals represented by A, B, C and D. A, B, C and D are not the actual chemical symbols for the metals. The student:

• added each metal to aqueous solutions of the metal nitrates

• observed whether a reaction took place.

Table 6 shows information about three of the reaction mixtures.

The ionic equation for Reaction 1 is:

Why is this a redox reaction?

Tick () one box.

Which of the four metals has the greatest tendency to form positive ions? Use Table 6. Tick (✓) one box.

The nitrate ion has the formula NO₃^– Which of the four metals could be aluminium? Explain your answer. Use Table 6.

Metal X is extracted from an oxide of metal X by reaction with hydrogen. The equation for the reaction is:

The percentage atom economy for obtaining metal X by this method is 77.3%. Calculate the relative atomic mass (A_r) of metal X. Relative atomic masses (A_r): H = 1 O = 16

This question is about silicon and compounds of silicon.

The reactivity series sometimes includes non-metals such as carbon, hydrogen and silicon. Silicon can be extracted by reducing silicon dioxide with different substances. The equation for one possible reaction is:

Explain what this reaction shows about the position of silicon in the reactivity series.

Aluminium also reduces silicon dioxide. Carbon is used rather than aluminium to reduce silicon dioxide because carbon is cheaper than aluminium. Carbon can be obtained by heating coal. Aluminium is obtained from aluminium oxide. Explain why aluminium is more expensive than carbon.

Magnesium also reduces silicon dioxide. The equation for the reaction is:

Give one reason why the products are difficult to separate if magnesium is used to reduce silicon dioxide.

Calculate the minimum mass in grams of magnesium needed to completely reduce 1.2 kg of silicon dioxide. Relative atomic masses (A_r): O = 16 Mg = 24 Si = 28

Si₂H₆ is a covalent compound of silicon and hydrogen.

Complete Figure 9 to show the outer shell electrons in a molecule of Si₂H₆

Si₂H₆ reacts with oxygen. The equation for the reaction is:

30 cm³ of Si₂H₆ is reacted with 150 cm³ (an excess) of oxygen.

Calculate the total volume of gases present after the reaction. All volumes of gases are measured at the same temperature and pressure.

This question is about the extraction of metals.

Element R is extracted from its oxide by reduction with hydrogen.

The equation for the reaction is:

The sum of the relative formula masses (M_r) of the reactants (3 H₂ + RO₃) is 150

Calculate the relative atomic mass (A_r) of R.

Relative atomic masses (A_r): H = 1 O = 16

Identify element R.

You should use:

• your answer to question 10.1

• the periodic table.

Carbon is used to extract tin (Sn) from tin oxide (SnO₂).

The equation for the reaction is:

Calculate the percentage atom economy for extracting tin in this reaction.

Relative atomic masses (A_r): C = 12 O = 16 Sn = 119

Tungsten (W) is a metal.

Tungsten is extracted from tungsten oxide (WO₃).

All other solid products from the extraction method must be separated from the tungsten.

Table 9 shows information about three possible methods to extract tungsten from tungsten oxide.

Evaluate the three possible methods for extracting tungsten from tungsten oxide.

This question is about the extraction of metals.

Element R is extracted from its oxide by reduction with hydrogen. The equation for the reaction is:

The sum of the relative formula masses (M_r) of the reactants (3 H₂ + RO₃) is 150 Calculate the relative atomic mass (A_r) of R. Relative atomic masses (A_r): H = 1 O = 16

Identify element R. You should use:

• your answer to question 03.1

• the periodic table.

Identity of R =

Carbon is used to extract tin (Sn) from tin oxide (SnO₂). The equation for the reaction is:

Calculate the percentage atom economy for extracting tin in this reaction. Relative atomic masses (A_r): C = 12 O = 16 Sn = 119

Tungsten (W) is a metal. Tungsten is extracted from tungsten oxide (WO₃). All other solid products from the extraction method must be separated from the tungsten. Table 2 shows information about three possible methods to extract tungsten from tungsten oxide.

Evaluate the three possible methods for extracting tungsten from tungsten oxide.

This question is about the extraction of metals.

Tungsten is a metal. The symbol of tungsten is W Tungsten is produced from tungsten oxide by reaction with hydrogen. The equation for the reaction is:

Calculate the percentage atom economy when tungsten is produced in this reaction. Use the equation:

Relative formula masses (M_r): WO₃ = 232 H₂ = 2

Aluminium is extracted from aluminium oxide.

38% of a rock sample is aluminium oxide. Calculate the mass of aluminium oxide in 40 kg of the rock sample.

The formula of aluminium oxide is Al₂O₃ Calculate the relative formula mass (M_r) of aluminium oxide. Relative atomic masses (A_r): O = 16 Al = 27

60.0 kg of aluminium oxide produces a maximum of 31.8 kg of aluminium. In an extraction process only 28.4 kg of aluminium is produced from 60.0 kg of aluminium oxide. Calculate the percentage yield. Give your answer to 3 significant figures.

Use the equation:

Extracting metals by electrolysis is a very expensive process. Explain why aluminium is extracted using electrolysis and not by reduction with carbon.

This question is about metals and metal compounds.

Iron pyrites is an ionic compound.

Figure 12 shows a structure for iron pyrites.

Determine the formula of iron pyrites.

Use Figure 12.

An atom of iron is represented as⁵⁶₂₆Fe

Give the number of protons, neutrons and electrons in this atom of iron.

Iron is a transition metal.

Sodium is a Group 1 metal.

Give two differences between the properties of iron and sodium.

Nickel is extracted from nickel oxide by reduction with carbon.

Explain why carbon can be used to extract nickel from nickel oxide.

This question is about metals and metal compounds.

Iron pyrites is an ionic compound. Figure 1 shows a structure for iron pyrites.

Determine the formula of iron pyrites. Use Figure 1.

An atom of iron is represented as⁵⁶₂₆Fe Give the number of protons, neutrons and electrons in this atom of iron.

Iron is a transition metal. Sodium is a Group 1 metal. Give two differences between the properties of iron and sodium.

Nickel is extracted from nickel oxide by reduction with carbon.

Explain why carbon can be used to extract nickel from nickel oxide.

An equation for the reaction is:

Calculate the percentage atom economy for the reaction to produce nickel. Relative atomic masses (A_r): C = 12 Ni = 59 Relative formula mass (M_r): NiO = 75 Give your answer to 3 significant figures.

Titanium is a transition metal. Titanium is extracted from titanium dioxide in a two stage industrial process. Stage 1 TiO₂ + 2 C + 2 Cl₂ TiCl₄ + 2 CO Stage 2 TiCl₄ + 4 Na Ti + 4 NaCl

Suggest one hazard associated with Stage 1.

Water must be kept away from the reaction in Stage 2. Give one reason why it would be hazardous if water came into contact with sodium.

Suggest why the reaction in Stage 2 is carried out in an atmosphere of argon and not in air.

Titanium chloride is a liquid at room temperature. Explain why you would not expect titanium chloride to be a liquid at room temperature.

In Stage 2, sodium displaces titanium from titanium chloride.

Sodium atoms are oxidised to sodium ions in this reaction. Why is this an oxidation reaction?

Complete the half equation for the oxidation reaction.

In Stage 2, 40 kg of titanium chloride was added to 20 kg of sodium. The equation for the reaction is:

Relative atomic masses (A_r): Na = 23 Cl = 35.5 Ti = 48 Explain why titanium chloride is the limiting reactant. You must show your working.

For a Stage 2 reaction the percentage yield was 92.3% The theoretical maximum mass of titanium produced in this batch was 13.5 kg. Calculate the actual mass of titanium produced.