Nitrogen is the most abundant gas in the Earth's atmosphere today. What is the approximate percentage of the second most abundant gas, oxygen, in today's dry atmosphere?
0.04%0.04\%0.04%
0.9%0.9\%0.9%
21%21\%21%
78%78\%78%
Practise Edexcel GCSE Chemistry Earth and atmospheric science with exam-style questions for Foundation and Higher tier. 62 questions, matched to the Edexcel GCSE Chemistry (1CH0) specification and written in Paper 1 and Paper 2 style. Every question includes a full worked solution and mark scheme, so you can see where marks are awarded rather than just whether you got the answer right.
