Pearson Edexcel International GCSE (9–1) · CHEMISTRY · Section
Preventing rusting by using sacrificial protection
18 practice questions
Practice questions
1–8 of 8 · Normal
Question 1
2 marks · Normal
Answer and see the solution →Describe how sacrificial protection prevents iron from rusting.
Question 2
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 3
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.
Question 4
3 marks · Normal
Answer and see the solution →Rusting occurs when iron is exposed to air and water. Ships are often fitted with blocks of zinc on their hulls.
(a)[3 marks]Explain, using the ideas of oxidation and reactivity, how these zinc blocks prevent the iron hull from rusting.
Question 5
4 marks · Normal
Answer and see the solution →A scientist is choosing a metal to protect an iron water tank from rusting. She tests three metals (A, B, and C), each attached to iron and left in moist air. The results are shown below.
Results: Rusting of iron with different metals attached Metal attached Observation after 1 month A Iron is rusted; attached metal is not corroded B Iron is shiny; attached metal is heavily corroded C Iron is rusted; attached metal is also rusted (a)[2 marks]Which metal, A, B, or C, acts as a sacrificial anode for iron? Explain your answer.
(b)[2 marks]Explain, using the observations, why the chosen metal must be more reactive than iron.
Question 6
1 mark · Normal
Answer and check →Which structure is commonly protected using sacrificial anodes made of zinc or magnesium?
- A.Aluminium can
- B.Underground oil pipeline
- C.Plastic water bottle
- D.Glass window
Question 7
2 marks · Normal
Answer and see the solution →State what is meant by a sacrificial anode, and name a metal commonly used as one to protect iron.
Question 8
4 marks · Normal
Answer and see the solution →A section of an underwater steel bridge has several aluminium blocks attached to it.
(a)[2 marks]Explain why aluminium is able to protect the steel from rusting by sacrificial protection.
(b)[2 marks]Describe what happens to the aluminium blocks over time and why they are eventually replaced.