4CH1
Extraction and Uses of Metals
Inorganic Chemistry
Exam Frequency Analysis
Past paper frequency (2018 to 2024)
This topic accounts for approximately 6% of your exam marks.
stable
Low
Stable6%
Blast furnace chemistry and electrolytic extraction of aluminium regularly examined.
Aluminium
| Use | Property that matters |
|---|---|
| Aircraft and high-speed train bodies | Low density; high strength-to-weight ratio |
| Saucepans and cookware | Good thermal conductor; unreactive with most foods |
| Overhead power cables | Good electrical conductor; lighter than copper |
| Drink cans and food containers | Non-toxic; resists corrosion thanks to its surface oxide layer |
Copper
| Use | Property that matters |
|---|---|
| Electrical wiring inside houses and devices | Excellent electrical conductor; ductile (draws into wires) |
| Plumbing pipes and tanks | Unreactive with water; malleable so easy to bend; non-toxic |
| Heat exchangers and base layers of cookware | Excellent thermal conductor |
Iron and steel
- Pure iron is too soft and corrodes too easily for most engineering uses; almost all iron is converted into , an alloy of iron with a controlled amount of carbon and sometimes other metals
- Iron itself is used as a heterogeneous catalyst in the industrial Haber process for ammonia and in some other large-scale reactions
| Type of steel | Composition | Typical use | Why this composition |
|---|---|---|---|
| Mild steel | Iron + about 0.25% carbon | Car body panels, nails, wiring | Soft, malleable, easy to press and shape |
| High-carbon steel | Iron + 0.5–1.4% carbon | Cutting tools, drill bits, chisels | Hard, holds a sharp edge |
| Stainless steel | Iron + about 18% chromium + 8% nickel | Cutlery, sinks, chemical plant | Strong; chromium oxide layer prevents corrosion |