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Scientists believe that, about 4500 million years ago, the Earth was very much hotter than it is now - Edexcel - GCSE Chemistry - Question 2 - 2012 - Paper 1
Question 2
Scientists believe that, about 4500 million years ago, the Earth was very much hotter than it is now. The atmosphere then was very different from that on Earth today... show full transcript
Worked Solution & Example Answer:Scientists believe that, about 4500 million years ago, the Earth was very much hotter than it is now - Edexcel - GCSE Chemistry - Question 2 - 2012 - Paper 1
Step 1
Explain why it is difficult to be precise about the composition of the Earth’s early atmosphere.
Answer
Determining the precise composition of the early atmosphere is challenging for a few reasons. Firstly, there are no direct measurements or written records from that time period, which makes it hard to have accurate data. Additionally, the evidence gathered from ice cores and rock samples can be limited or unreliable, as they may not provide a complete picture of the early atmospheric conditions. Finally, varying interpretations from different scientific sources can lead to conflicting information about what the atmosphere contained.
Step 2
How did this affect the composition of the atmosphere?
Answer
The formation of oceans significantly affected the atmosphere's composition by lowering the levels of water vapor and carbon dioxide. Oceans acted as a sink, absorbing these gases, which led to a change in the atmospheric balance.
Step 3
Explain how the growth of these plants affected the composition of the atmosphere.
Answer
The growth of the first plants had a profound impact on the atmosphere. Through the process of photosynthesis, plants absorbed carbon dioxide and released oxygen. This process not only decreased the concentration of carbon dioxide but also increased oxygen levels in the atmosphere, fundamentally altering its composition.
Step 4