Alloys And Their Properties
Overview
Pure metals are often too soft or too easily corroded for the jobs we ask of them. So we mix them. An alloy, a metal blended with other elements, can be harder, stronger and more resistant to rusting than the pure metal it came from, which is why brass instruments, stainless-steel cutlery and aircraft bodies are all alloys.
In this lesson you will learn what an alloy is, meet brass and stainless steel and what they are made from, and see why alloys are more useful than pure metals. You will also explain, in terms of structure, exactly why mixing different-sized atoms makes a metal harder and stronger.
Objectives
- Describe an alloy as a mixture of a metal with other elements, including: (a) brass as a mixture of copper and zinc (b) stainless steel as a mixture of iron and other elements such as chromium, nickel and carbon.
- State that alloys can be harder and stronger than the pure metals and are more useful.
- Describe the uses of alloys in terms of their physical properties, including stainless steel in cutlery because of its hardness and resistance to rusting.
- Identify representations of alloys from diagrams of structure.
- [Supplement] Explain in terms of structure how alloys can be harder and stronger than the pure metals because the different sized atoms in alloys mean the layers can no longer slide over each other.
Lesson Note
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Lesson Evaluation
Congratulations on completing the lesson on Alloys And Their Properties. 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.
- What is an alloy? A. a pure metal B. a mixture of a metal with other elements C. a non-metal element D. a compound of two non-metals Answer: B
- Brass is an alloy of: A. iron and carbon B. copper and tin C. copper and zinc D. iron and chromium Answer: C
- Stainless steel resists rusting mainly because it contains: A. carbon B. zinc C. chromium D. tin Answer: C
- Alloys are generally: A. softer than pure metals B. harder and stronger than pure metals C. always liquids D. poor conductors Answer: B
- An alloy is harder than a pure metal because the different-sized atoms: A. make the metal lighter B. stop the layers sliding over each other C. react with each other D. lower the melting point Answer: B
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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