Using materials (chemistry only)

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Question 6
Easy

This question is about alloys.

Brass is an alloy of copper and zinc.

Diagram showing two atomic arrangements. On the left is 'Pure copper', consisting of a regular, closely packed grid of identical light grey circles representing copper atoms, arranged in neat horizontal layers. On the right is 'Brass', showing a mixture where some of the light grey copper atoms are replaced by larger dark grey circles representing zinc atoms, which distorts the regular layered pattern. Key: light grey circle = copper atom; larger dark grey circle = zinc atom.

a.

A sample of brass has 7 zinc atoms for every 18 copper atoms. Determine the percentage of atoms in this sample of brass that are zinc atoms.

[2]
b.

Explain why brass is harder than pure copper. Complete the sentences:

  • "This is because the atoms of copper and zinc have different _______________."
  • "Therefore, the layers of atoms cannot easily _______________."
[2]

Using materials (chemistry only) Questions

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