5361862
Description
Flashcards by Princess Terin, updated more than 1 year ago
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Created by Princess Terin
over 9 years ago
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| Question | Answer |
| Where did the gases that formed the Earths early atmosphere come from? | Volcanic activity |
| How much oxygen was present in the Earths early atmosphere? | Little/none |
| How much Carbon Dioxide was present in the Earths early atmosphere? | lots (18%) |
| Name 4 other gases present in the Earth’s early atmosphere. | Nitrogen, ammonia, methane, water vapour |
| How do scientists use rocks to work out the composition of the Earth’s early atmosphere? | Analyse the minerals in them and look for oxides. |
| How do scientists believe the oceans were formed? | Condensation of water vapour |
| Describe two ways that the carbon dioxide levels in the early atmosphere were reduced. | It dissolved in oceans and was locked up in sedimentary rocks |
| What mineral is limestone made from? | Calcium Carbonate |
| How did photosynthesis affect the composition of the atmosphere? | Removed Carbon Dioxide, added Oxygen |
| What is the current composition of the Earths atmosphere | Nitrogen 78% Oxygen 21% Argon 0.9% Carbon Dioxide 0.04% other trace% |
| State 3 ways humans changed the composition of the atmosphere. | Burning fossil fuels, farming, deforestation |
| What 2 main gases do volcanoes release in to the atmosphere | Nitrogen and Carbon dioxide |
| What effect does deforestation have on the amount of carbon dioxide in the atmosphere, explain | Increases it as trees are no longer able to remove carbon dioxide through photosynthesis. |
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