Atom economy

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 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 electrolysis.

Ionic compounds decompose when they are electrolysed.

A student electrolyses sodium sulfate solution.

Figure 13 shows the apparatus used.

Sodium sulfate solution contains:

• hydrogen ions

• hydroxide ions

• sodium ions

• sulfate ions.

Oxygen is produced at the positive electrode.

Which ions are discharged at the positive electrode to produce oxygen?

Tick (✓) one box.

Figure 14 shows one of the measuring cylinders during the electrolysis.

What is the volume of gas in the measuring cylinder?

Ionic compounds can be electrolysed when molten or dissolved in water.

Why can ionic compounds not be electrolysed when solid?

You should answer in terms of ions.

Table 7 shows the products of electrolysis of two molten compounds.

Complete Table 7.

The electrolysis of molten sodium chloride is used to extract sodium metal.

Why is sodium metal extracted by electrolysis instead of by reduction with carbon?

Tick (✓) one box.

What is the state symbol for molten sodium chloride?

Tick (✓) one box.

Titanium can be produced from titanium oxide by electrolysis.

The equation for the reaction is:

Calculate the percentage atom economy for the production of titanium from titanium oxide by electrolysis.

Use the equation:

Relative atomic mass (A_r): Ti = 48

Relative formula mass (M_r): TiO₂ = 80

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 silver iodide. Silver iodide is produced in the reaction between silver nitrate solution and sodium iodide solution. The equation for the reaction is: AgNO₃(aq) + NaI(aq) → AgI(s) + NaNO₃(aq)

A student investigated the law of conservation of mass. This is the method used.

1. Pour silver nitrate solution into a beaker labelled A.

2. Pour sodium iodide solution into a beaker labelled B.

3. Measure the masses of both beakers and their contents.

4. Pour the solution from beaker B into beaker A.

5. Measure the masses of both beakers and their contents again.

Table 7 shows the student’s results.

Explain how the results demonstrate the law of conservation of mass. You should use data from Table 7 in your answer.

Suggest how the student could separate the insoluble silver iodide from the mixture at the end of the reaction.

The student purified the separated silver iodide. This is the method used.

1. Rinse the silver iodide with distilled water.

2. Warm the silver iodide.

Suggest one impurity that was removed by rinsing with water.

Suggest why the student warmed the silver iodide.

Calculate the percentage atom economy for the production of silver iodide in this reaction. The equation for the reaction is: AgNO₃(aq) + NaI(aq) → AgI(s) + NaNO₃(aq) Give your answer to 3 significant figures. Relative formula masses (M_r): AgNO₃ = 170 NaI = 150 AgI = 235 NaNO₃ = 85

Give one reason why reactions with a high atom economy are used in industry.

This question is about silver iodide. Silver iodide is produced in the reaction between silver nitrate solution and sodium iodide solution. The equation for the reaction is: AgNO₃(aq) + NaI(aq) → AgI(s) + NaNO₃(aq)

A student investigated the law of conservation of mass. This is the method used.

1. Pour silver nitrate solution into a beaker labelled A.

2. Pour sodium iodide solution into a beaker labelled B.

3. Measure the masses of both beakers and their contents.

4. Pour the solution from beaker B into beaker A.

5. Measure the masses of both beakers and their contents again.

Table 3 shows the student’s results.

Explain how the results demonstrate the law of conservation of mass. You should use data from Table 3 in your answer.

Suggest how the student could separate the insoluble silver iodide from the mixture at the end of the reaction.

The student purified the separated silver iodide. This is the method used.

1. Rinse the silver iodide with distilled water.

2. Warm the silver iodide.

Suggest one impurity that was removed by rinsing with water.

Suggest why the student warmed the silver iodide.

Calculate the percentage atom economy for the production of silver iodide in this reaction. The equation for the reaction is: AgNO₃(aq) + NaI(aq) → AgI(s) + NaNO₃(aq) Give your answer to 3 significant figures. Relative formula masses (M_r): AgNO₃ = 170 NaI = 150 AgI = 235 NaNO₃ = 85

Give one reason why reactions with a high atom economy are used in industry.

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.