Showing that air contains about one-fifth oxygen
3 marks · EasyAnswer the following about the gases in dry, unpolluted air.
Name the most abundant gas in dry air.
State the gas present in the smallest amount from the main four gases.
Give the percentage by volume of carbon dioxide in dry air, to two decimal places.
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(a) Nitrogen
(b) Carbon dioxide
(c) 0.04%
Common mistakes: Argon as smallest, wrong percent for CO2
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Marking points
A1 (a) · 1 mark · Correctly names nitrogen as most abundant gas.
B1 (b) · 1 mark · Correctly identifies carbon dioxide as least abundant of main four gases.
C1 (c) · 1 mark · Accurately states percentage as 0.04%.
Worked solution
a) Nitrogen b) Carbon dioxide c) 0.04%