Pearson Edexcel International GCSE (9–1) · CHEMISTRY · Section
Preventing rusting by using sacrificial protection
18 practice questions
Practice questions
1–10 of 18
Question 1
1 mark · Easy
Answer and see the solution →State one example of a structure that is protected from rusting using sacrificial anodes.
Question 2
3 marks · Easy
Answer and see the solution →Iron pipes used in water supply networks are often fitted with zinc blocks to prevent rusting.
(a)[1 mark]Describe what happens to the zinc block over time.
(b)[2 marks]Explain how the zinc block prevents the iron pipe from rusting.
Question 3
2 marks · Easy
Answer and see the solution →A large storage tank for water is made of steel and is buried underground. Magnesium blocks are attached to its surface.
Explain why magnesium is a suitable choice to protect the tank and suggest one other metal that could be used for this purpose.
Question 4
3 marks · Easy
Answer and see the solution →The table shows how the mass of a zinc sacrificial anode attached to an iron structure changes over four years.
Year Mass of zinc anode (g) 0 500 1 425 2 355 3 295 4 240 (a)[1 mark]State the decrease in mass of the zinc anode during the second year (from year 1 to year 2).
(b)[1 mark]Explain why the zinc anode loses mass over time.
(c)[1 mark]Describe how this process protects the iron structure from rusting.
Question 5
1 mark · Easy
Answer and see the solution →State why a sacrificial anode used to protect iron must be more reactive than iron.
Question 6
3 marks · Easy
Answer and see the solution →Some large steel structures are fitted with blocks of magnesium for protection.
(a)[1 mark]State what these magnesium blocks are called.
(b)[2 marks]Describe how these magnesium blocks help prevent the steel structure from rusting.
Question 7
2 marks · Easy
Answer and see the solution →An iron water tank is protected from rust by a zinc block acting as a sacrificial anode. Over 24 months, the mass of the zinc block decreases from 800 g to 620 g.
Calculate the average mass of zinc lost per month. Show your working.
Question 8
2 marks · Normal
Answer and see the solution →Describe how sacrificial protection prevents iron from rusting.
Question 9
4 marks · Normal
Answer and see the solution →The diagram shows an iron pipeline buried underground with blocks of magnesium attached at intervals.
(a)[2 marks]Explain why the magnesium blocks must be more reactive than iron in order to protect the pipeline from rusting.
(b)[2 marks]Explain what happens to the magnesium during this process.
Question 10
3 marks · Normal
Answer and see the solution →A ship’s iron hull is protected from rusting by sacrificial anodes. Each anode is made from magnesium and has a mass of 6 kg. Over a year, each anode loses 1.5 kg of magnesium.
(a)[1 mark]State one structure, apart from a ship, that is protected by sacrificial anodes.
(b)[2 marks]Calculate the percentage of magnesium lost from each anode in a year.