Showing that air contains about one-fifth oxygen

3 marks · Easy

The table below shows the major gases in dry, unpolluted air.

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Must show: Nitrogen: 78.1, Oxygen: 21.0, Argon: 0.9, Carbon dioxide: 0.04

Also accept: Nitrogen: 78; Oxygen: 21; Argon: 1; Carbon dioxide: 0.04

Common mistakes: Numbers swapped or rounded incorrectly

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Marking points

I1 · 1 mark · Correctly fills nitrogen: 78.1 (%)

I2 · 1 mark · Correctly fills oxygen: 21.0 (%)

I3 · 1 mark · Correctly fills argon (0.9%) and carbon dioxide (0.04%)

Worked solution