Alloys as Useful Materials
Revise Alloys as Useful Materials for GCSE Chemistry with this free worksheet and full mark scheme — Foundation and Higher exam-style questions with worked answers for AQA, Edexcel and OCR. A separate (triple) chemistry topic on useful alloys such as steel, bronze, brass and gold alloys, and why they outperform pure metals.
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These worksheets and mark schemes are original, written for Virtus Academy and checked against the current AQA, Edexcel and OCR specifications. Every worksheet comes with a full mark scheme.
Topic overview
Most metals in everyday use are alloys, because pure metals are often too soft. This is a Triple-only topic.
Bronze is an alloy of copper and tin, used for statues and decorative objects. Brass is an alloy of copper and zinc, used for fittings and instruments. Gold used in jewellery is an alloy with silver, copper and zinc, and its purity is measured in carats, with 24 carat being pure gold.
Steels are alloys of iron with carbon and sometimes other metals. High carbon steel is strong but brittle; low carbon steel is softer and more easily shaped. Stainless steel contains chromium and nickel, making it hard and resistant to corrosion.
Revision notes
Copper alloys and gold
Bronze: copper and tin, used for statues and decorative objects.
Brass: copper and zinc, used for fittings and musical instruments. Gold for jewellery is alloyed with silver, copper and zinc; purity is measured in carats, with 24 carat being 100 per cent gold.
Steels
Steels are alloys of iron containing specific amounts of carbon and sometimes other metals.
High carbon steel is strong but brittle. Low carbon steel is softer and more easily shaped. Stainless steel contains chromium and nickel, making it hard and resistant to corrosion.
Aluminium alloys
Aluminium alloys have low density, which makes them valuable where weight matters.
They are used in aircraft and vehicles. As with all alloys, the added atoms distort the layers so the alloy is harder than the pure metal.
Key points
- Bronze is copper and tin.
- Brass is copper and zinc.
- Gold purity is measured in carats.
- 24 carat gold is pure gold.
- High carbon steel is strong but brittle.
- Stainless steel resists corrosion.
Worked examples
Example 1
Name the two metals in bronze and the two in brass. [2 marks]
Model answer
Bronze contains copper and tin (1 mark). Brass contains copper and zinc (1 mark).
Example 2
Explain the difference in properties between high carbon steel and low carbon steel. [2 marks]
Model answer
High carbon steel is strong but brittle (1 mark). Low carbon steel is softer and more easily shaped (1 mark).
Example 3
Explain why stainless steel is used for cutlery. [2 marks]
Model answer
Stainless steel contains chromium and nickel, which make it resistant to corrosion (1 mark), so it does not rust when repeatedly washed and exposed to water (1 mark).
Common mistakes
Confusing bronze and brass.
Bronze is copper and tin; brass is copper and zinc.
Saying 24 carat gold is an alloy.
24 carat is pure gold. Lower carat values indicate alloys.
Getting the steel properties backwards.
High carbon is strong but brittle; low carbon is softer and more shapeable.
Saying stainless steel cannot corrode at all.
It is highly resistant, which is not quite the same as immune.
Exam tips
- Learn the composition of each named alloy.
- Contrast high and low carbon steel directly.
- Link each alloy to a use justified by its properties.
- Remember this is a Triple-only topic.
Key terms
- Alloy
- A mixture of a metal with other elements.
- Bronze
- An alloy of copper and tin.
- Brass
- An alloy of copper and zinc.
- Carat
- A measure of gold purity, 24 carat being pure.
Related topics
Written and reviewed against the current AQA, Edexcel and OCR specifications. Spotted an error? Let us know.