Table 1 shows the estimated percentages of different gases in the Earth's early atmosphere compared with the atmosphere today.
| Gas | Percentage (%) in Earth's early atmosphere | Percentage (%) in today's atmosphere |
|---|---|---|
| carbon dioxide | 96.0 | 0.04 |
| nitrogen | 3.0 | 78.0 |
| Gas Q | <0.1 | 21.0 |
| argon | <0.1 | 0.9 |
| methane | 0.5 | <0.001 |
| ammonia | 0.4 | <0.001 |
Explain, using the data in Table 1, the identity of Gas Q.
97 exam-style questions on Edexcel GCSE Chemistry 9.2 Earth and atmospheric science, covering 9.2.1 The Earth's early atmosphere, 9.2.2 How the atmosphere evolved, 9.2.3 Chemical test for oxygen, and 9.2.4 The greenhouse effect and climate change. Each one has a worked solution and a mark scheme showing where the marks go.