2.5.3Inorganic Chemistry
Using Metals — Edexcel Linear - OL (Chemistry) Revision Notes & Topical Questions
5 min read 5 parts Lesson 18 of 23 Unit quiz
Part 1 of 5Properties of Metals
A material is chosen for a job because its properties match what the job needs.
Conductivity
- Metals conduct electricity and heat well because of delocalised electrons that move through the structure.
Malleable and ductile
- Layers of atoms can slide over each other, so metals can be hammered into shape or drawn into wires.
Strength
- Many metals are strong, but this varies, and strength is balanced against density and cost.
Reactivity
- Metals low in the reactivity series resist corrosion, so are suited to water pipes and cookware.
Part 2 of 5Aluminium and Copper
Aluminium and Copper
Aluminium for aircraft
- Aluminium has low density with good strength, so aircraft bodies are light and strong.
Aluminium for cables
- Overhead cables use aluminium as it conducts electricity well and is light enough to hang from pylons.
Aluminium for cans and pans
- It resists corrosion, is non-toxic and conducts heat well, which suits food cans and saucepans.
Copper for wiring
- Copper is an excellent electrical conductor and ductile, so it can be drawn into wires.
Copper for pipes
- Copper does not react with water, is malleable and non-toxic, so it is used for water pipes.
| Metal | Use | Key property |
|---|---|---|
| Aluminium | Aircraft bodies | Low density, strong |
| Aluminium | Overhead cables | Good conductor, light |
| Copper | Electrical wiring | Good conductor, ductile |
| Copper | Water pipes | Unreactive, malleable |
Part 3 of 5Iron and Steel
Iron and Steel
Iron as a building material
- Iron and steel are strong, malleable and relatively cheap, so they are used in construction.
Iron as a catalyst
- Iron is used as the catalyst in the Haber process for making ammonia.
Mild steel
- Mild steel is soft and malleable, so it is shaped easily into car body panels.
High carbon steel
- With more carbon, steel is hard and is used for tools such as chisels.
Stainless steel
- Stainless steel contains chromium and nickel, resists corrosion and is used for cutlery and sinks.
Part 4 of 5Choosing a Metal for a Job
1
List the properties the job requires, such as conductivity, strength or low density.
2
Compare these with the properties of candidate metals.
3
Consider reactivity, because corrosion can shorten the life of a product.
4
Consider cost and whether the metal is safe to use with food or drinking water.
5
Select the metal or alloy that matches the most important requirements.
Part 5 of 5Exam Checklist & Tips
2.5.3 – Key Points for the Exam
- Malleable Able to be hammered or pressed into shape without breaking.
- Ductile Able to be drawn out into wires.
- Corrosion Gradual destruction of a metal by reaction with substances in the environment.
- Catalyst A substance that speeds up a reaction and is not used up.
Common Mistakes
- Saying aluminium is used for cables only because it is cheap; its low density and conductivity matter.
- Forgetting that stainless steel is an alloy, not a pure metal.
- Using vague words like 'strong' without linking the property to the use.
- Stating that copper pipes are chosen because copper is reactive.
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