A computer model follows 200 000 tonnes of carbon that was initially present in carbon dioxide in the Earth's early atmosphere.
The table shows the mass of this carbon stored in three places at the end of the modelled period.
| Carbon store | Mass of carbon in tonnes |
|---|---|
| Living biomass | 18 000 |
| Carbonate sediments | 64 000 |
| Fossil fuels | 28 000 |
Calculate the percentage of the initial carbon that was transferred from the atmosphere into the three stores.
Explain how carbon from atmospheric carbon dioxide became stored in carbonate sediments and fossil fuels.
79 exam-style questions on AQA GCSE Chemistry 9.1 The composition and evolution of the Earth's atmosphere, covering 9.1.1 The proportions of different gases in the atmosphere, 9.1.2 The Earth's early atmosphere, 9.1.3 How oxygen increased, and 9.1.4 How carbon dioxide decreased. Each one has a worked solution and a mark scheme showing where the marks go.