New
New
Year 10
OCR
Higher

Alloys and their properties

I can compare pure metals with their alloys, and give examples of alloys and their uses.

New
New
Year 10
OCR
Higher

Alloys and their properties

I can compare pure metals with their alloys, and give examples of alloys and their uses.

Lesson details

Key learning points

  1. Iron is alloyed with other metals to produce steel alloys.
  2. Copper is alloyed with other metals to make multiple useful alloys.
  3. Gold, aluminium, and magnesium all form useful alloys with other metals.

Common misconception

Pupils often find it difficult to apply what they have learnt about alloys when asked about an unfamiliar one, or when provided with a table of data.

Provide pupils with a range of different examples of alloys. Give them plenty of practice of comparing the properties of the alloy with those of the pure metal.

Keywords

  • Alloy - A mixture of two or more elements, where at least one element is a metal.

  • Steel - An alloy of iron that contains specific amounts of carbon and may contain other metals.

  • Carat - A unit for measuring the purity of gold.

  • Brittle - A substance that has the ability to break up easily.

Where possible, provide samples of pure metals and alloys so that the pupils can see the differences for themselves: for example iron and steel or lead, tin and solder.
Teacher tip

Equipment

None required.

Licence

This content is © Oak National Academy Limited (2024), licensed on Open Government Licence version 3.0 except where otherwise stated. See Oak's terms & conditions (Collection 2).

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6 Questions

Q1.
Which of the following best describes an alloy?
Correct answer: A mixture
A compound
An element
An atom
Q2.
Metallic bonding consists of metal ions in a 'sea' of .
Correct Answer: delocalised electrons
Q3.
Why are pure metals ductile?
Correct answer: Metal ions are arranged in layers that can slide over one another.
Delocalised electrons are free to move through the metal.
Strong electrostatic attraction between metal ions and delocalised electrons.
Q4.
Is this statement true or false? Pure metals are generally more malleable than their alloy counterparts.
Correct answer: True
False
Q5.
What is 25% of 50.0? Give your answer to 3 significant figures.
Correct Answer: 12.5
Q6.
Why do metals have high melting points?
Metal ions are arranged in layers that can slide over one another.
Delocalised electrons are free to move through the metal.
Correct answer: Strong electrostatic attraction between metal ions and delocalised electrons.

6 Questions

Q1.
Match the following terms to the correct definition.
Correct Answer:Carat, a measure of the purity of gold

a measure of the purity of gold

Correct Answer:Brittle,hard but breaks easily

hard but breaks easily

Correct Answer:Steel,alloy of iron

alloy of iron

Q2.
Which two metals are found in the alloy bronze?
Correct answer: Copper
Correct answer: Tin
Zinc
Iron
Q3.
Which of the following statements about steel are correct?
Correct answer: Steel is harder than pure iron.
Steel is more malleable than pure iron.
Steel is more ductile than pure iron.
Correct answer: Steel is more resistant to corrosion than pure iron.
Q4.
Which of the following are examples of alloys?
Correct answer: 18-carat gold
Correct answer: Brass
Zinc
24-carat gold
Q5.
A 0.500 kg piece of copper alloy contains 27% aluminium. What mass of aluminium does it contain? Give your answer to three significant figures.
Correct Answer: 0.135 kg, 0.135, 0.135kg
Q6.
Why do metal alloys usually have lower melting points than the metals they are made from?
Correct answer: There are different sized ions in the structure.
There are delocalised electrons in the structure.
Correct answer: The bonds between the ions and electrons are weaker.
There is a regular lattice structure.