Corrosion Of Metals
Overview
Every year, vast sums are spent replacing iron and steel that has crumbled into orange-brown rust. Rusting is a slow chemical attack that needs just two things from the environment, and once you know what they are, you know how to stop it. Protecting metal from corrosion is one of the most practical applications of chemistry.
In this lesson you will learn the conditions needed for iron to rust, the barrier methods that keep it dry and airtight, and the clever use of a more reactive metal in galvanising and sacrificial protection. You will explain sacrificial protection in terms of the reactivity series and the loss of electrons.
Objectives
- State the conditions required for the rusting of iron and steel to form hydrated iron(III) oxide.
- State some common barrier methods, including painting, greasing and coating with plastic.
- Describe how barrier methods prevent rusting by excluding oxygen or water.
- [Supplement] Describe the use of zinc in galvanising as an example of a barrier method and sacrificial protection.
- [Supplement] Explain sacrificial protection in terms of the reactivity series and in terms of electron loss.
Lesson Note
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Lesson Evaluation
Congratulations on completing the lesson on Corrosion Of Metals. Now that youve explored the key concepts and ideas, its time to put your knowledge to the test. This section offers a variety of practice questions designed to reinforce your understanding and help you gauge your grasp of the material.
You will encounter a mix of question types, including multiple-choice questions, short answer questions, and essay questions. Each question is thoughtfully crafted to assess different aspects of your knowledge and critical thinking skills.
Use this evaluation section as an opportunity to reinforce your understanding of the topic and to identify any areas where you may need additional study. Don't be discouraged by any challenges you encounter; instead, view them as opportunities for growth and improvement.
- Which two substances are needed for iron to rust? A. oxygen and carbon dioxide B. water and oxygen C. water and nitrogen D. salt and oxygen only Answer: B
- Rust is mainly: A. iron(II) oxide B. hydrated iron(III) oxide C. iron carbonate D. iron sulfide Answer: B
- Which is a barrier method of rust prevention? A. galvanising B. sacrificial protection C. painting D. attaching magnesium blocks Answer: C
- In sacrificial protection of iron, the metal used must be: A. less reactive than iron B. more reactive than iron C. a non-metal D. the same as iron Answer: B
- Galvanising protects steel by: A. only acting as a barrier B. only sacrificial protection C. acting as a barrier and by sacrificial protection D. making the steel more reactive Answer: C
Available on the Green Bridge App
Download the Green Bridge CBT app on your phone or computer to access full lesson notes, practice questions, and more.
Available on the Green Bridge App
Download the Green Bridge CBT app on your phone or computer to access full lesson notes, practice questions, and more.
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