Pearson Edexcel International GCSE (9–1) · CHEMISTRY · Section
Preventing rusting by galvanising
21 practice questions
Practice questions
11–20 of 21
Question 11
3 marks · Normal
Answer and see the solution →Explain why covering iron with a plastic coat is less effective at preventing rust than galvanising, especially if the plastic is damaged.
Question 12
4 marks · Normal
Answer and see the solution →The table shows observations of iron nails kept under different conditions for two weeks.
Test tube Condition Rust observed after 2 weeks? A Nail in dry air (no water) No B Nail in boiled water, oil layer on top (no air) No C Nail in ordinary water, exposed to air Yes (a)[2 marks]Use the data to state the two conditions needed for rusting.
(b)[1 mark]Suggest why no rust formed in test tube B.
(c)[1 mark]Explain why rusting happened in test tube C.
Question 13
1 mark · Normal
Answer and check →Which statement best explains how galvanising prevents rusting of iron?
- A.Zinc forms a hard barrier that cannot be scratched.
- B.Zinc reacts with water to make rust.
- C.Zinc is more reactive than iron and corrodes first.
- D.Zinc keeps air away by making the iron heavier.
Question 14
2 marks · Normal
Answer and see the solution →State why rusting is more rapid in salty water than in pure water.
Question 15
4 marks · Normal
Answer and see the solution →A bicycle frame made from iron is left outside in the rain.
(a)[1 mark]State the two conditions required for rusting of iron to occur.
(b)[1 mark]Describe how painting the bicycle frame prevents rusting.
(c)[2 marks]Explain why coating the frame with zinc protects the iron even if the paint or zinc layer is scratched, using the idea of the reactivity series.
Question 16
2 marks · Normal
Answer and see the solution →State the two conditions necessary for iron to rust. Describe briefly how galvanising prevents rusting.
Question 17
4 marks · Normal
Answer and see the solution →A farmer is installing a new iron gate that will be exposed to rain and air.
(a)[1 mark]Explain why the gate will rust if left unprotected.
(b)[2 marks]Describe two ways, other than galvanising, that could prevent the gate from rusting.
(c)[1 mark]State and explain why galvanising remains effective even if the zinc coating is scratched.
Question 18
3 marks · Normal
Answer and see the solution →A section of iron gutter is to be protected from rusting by galvanising. The gutter is 2.5 m long and each square metre of iron requires 80 g of zinc for an even, protective coating.
(a)[1 mark]State the two conditions required for rusting of iron to occur.
(b)[2 marks]The gutter has a surface area of 0.30 m². Calculate the minimum mass of zinc needed to galvanise the entire surface. Show your working and give your answer in grams.
Question 19
2 marks · Hard
Answer and see the solution →State the two conditions necessary for iron to rust. Explain why covering iron with zinc prevents rusting, even if the zinc layer is scratched.
Question 20
5 marks · Hard
Answer and see the solution →The diagram shows an iron pipe exposed outdoors. The owner wants to protect it from rusting using galvanising.
(a)[2 marks]Describe the process of galvanising as a method of preventing rusting.
(b)[2 marks]Explain why the pipe does not rust even if the zinc coating is damaged in places.
(c)[1 mark]State one other method, apart from galvanising, that could be used to prevent the pipe from rusting, and explain how it works.