Scientists use evidence from volcanoes today to suggest how the Earth's early atmosphere formed.
The table shows the composition of the gases released by an active volcano.
| Gas | Percentage by volume (%) |
|---|---|
| water vapour | 70 |
| carbon dioxide | 20 |
| sulfur dioxide | 6 |
| nitrogen | 3 |
| other gases | 1 |
Explain how the data in the table supports the idea that the Earth's early atmosphere was mainly carbon dioxide and water vapour.
The atmospheres of Mars and Venus are more than 95% carbon dioxide.
Suggest why scientists use this as evidence about the Earth's early atmosphere.
Water vapour made up a large percentage of the Earth's early atmosphere. Today it makes up only a small percentage.
Explain why.
Describe how the percentages of carbon dioxide and oxygen changed to produce the Earth's atmosphere today.
Complete the balanced symbol equation for photosynthesis.
6CO2+6H2O→C6H12O6+\mathrm{6CO_{2} + 6H_{2}O \rightarrow C_{6}H_{12}O_{6} +}6CO2+6H2O→C6H12O6+ ......
109 exam-style questions on OCR GCSE Chemistry 6.3 Interpreting and interacting with earth systems, covering 6.3.1 Formation and evolution of the atmosphere, 6.3.2 The greenhouse effect and climate change, 6.3.3 Sources and problems of atmospheric pollutants, and 6.3.4 Producing potable water. Each one has a worked solution and a mark scheme showing where the marks go.