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Why are alloys often more useful than pure metals, and why do we recycle metals?

The properties and uses of alloys, why alloys are harder than pure metals, and the economic and environmental reasons for recycling metals.

A focused answer to WJEC GCSE Chemistry topic 2.3 on alloys and recycling, covering what an alloy is, why alloys are harder than pure metals, common examples such as steel, and the economic and environmental reasons for recycling metals.

Generated by Claude Opus 4.88 min answer

Reviewed by: AI editorial process; not yet individually human-reviewed

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  1. What this topic is asking
  2. What an alloy is
  3. Why alloys are harder
  4. Recycling metals
  5. Try this

What this topic is asking

WJEC wants you to explain what alloys are, why they are usually harder than pure metals, and why metals are recycled. This is part of topic 2.3 Metals and their extraction in Unit 2 of WJEC GCSE Chemistry (3430).

What an alloy is

For example, steel is iron mixed with a small amount of carbon; brass is copper mixed with zinc; bronze is copper mixed with tin. Each alloy is chosen for a particular use.

Steel is the most important alloy because controlling the amount of carbon and adding other elements tunes its properties: low-carbon steel is soft and easily shaped for car bodies, high-carbon steel is hard for tools, and stainless steel contains chromium and nickel to resist rusting for cutlery and sinks. Pure iron on its own is too soft and rusts too readily for most of these jobs, which is why almost all iron is used as steel rather than as the pure metal.

Why alloys are harder

Recycling metals

Try this

Q1. Name the two elements in steel. [1 mark]

  • Cue. Iron and carbon.

Q2. State one environmental reason for recycling metals. [1 mark]

  • Cue. It conserves finite ore reserves (or reduces mining damage, or cuts landfill waste).

Exam-style practice questions

Practice questions written in the style of WJEC exam questions on this dot point, with worked answer explainers. The year tag is the paper they imitate, not the source.

WJEC 20193 marksExplain, in terms of structure, why an alloy such as steel is harder than pure iron.
Show worked answer →

A topic 2.3 Explain question on alloy structure. In a pure metal the atoms are the same size and arranged in regular layers that can slide over each other, so the metal is relatively soft (1 mark). An alloy contains atoms of different sizes, which distort the layers (1 mark) so the layers can no longer slide easily, making the alloy harder (1 mark). Markers reward the regular layers in the pure metal, the distortion by different-sized atoms, and the link to hardness. A common error is to say the atoms simply bond more strongly.

WJEC 20223 marksGive two reasons why recycling aluminium is better than extracting new aluminium from its ore.
Show worked answer →

A topic 2.3 evaluation question. Any two of: recycling uses much less energy than electrolysis of aluminium oxide, so it is cheaper and releases less carbon dioxide (1 mark); it conserves the limited ore reserves, which are finite (1 mark); it reduces waste sent to landfill and the environmental damage of mining (1 mark). Markers reward two distinct economic or environmental reasons. A common error is to give the same reason twice in different words.

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