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This question is about gases - AQA - GCSE Chemistry - Question 3 - 2018 - Paper 2
Question 3
This question is about gases. Figure 3 shows how nitrogen is used in the Haber Process to produce ammonia. **Figure 3** Gas X in Figure 3 is obtained from methane... show full transcript
Worked Solution & Example Answer:This question is about gases - AQA - GCSE Chemistry - Question 3 - 2018 - Paper 2
Step 2
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Explain the processes that led to these changes.
Answer
Several processes led to changes in the percentages of carbon dioxide and oxygen:
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Decreased Carbon Dioxide: Volcanic activity initially released water vapor, which condensed to form oceans.
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The oceans absorbed carbon dioxide, leading to a decrease in its atmospheric concentration.
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Photosynthetic algae and plants emerged, absorbing carbon dioxide and releasing oxygen.
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Increased Oxygen: Early oxygen was produced through photosynthesis, which significantly increased its levels in the atmosphere over time, locking carbon in sedimentary rocks and fossil fuels.
Step 5
Why are scientists not certain about the percentage of each gas in the Earth’s early atmosphere?
Answer
Scientists are not certain about the percentage of each gas in the Earth's early atmosphere due to the lack of direct evidence and the significant changes that occurred over billions of years, making accurate estimations challenging.