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The Earth’s early atmosphere was a mixture of gases - AQA - GCSE Chemistry - Question 5 - 2017 - Paper 1
Question 5
The Earth’s early atmosphere was a mixture of gases. One theory is that the Earth’s early atmosphere had the composition shown in Table 4. Table 4 Gas ... show full transcript
Worked Solution & Example Answer:The Earth’s early atmosphere was a mixture of gases - AQA - GCSE Chemistry - Question 5 - 2017 - Paper 1
Step 1
Amino acids are at the basis of all life processes. Suggest one reason why this conclusion may not be correct.
Answer
One potential reason could be that not all the necessary conditions for the formation of amino acids were replicated in Miller and Urey's experiment. For instance, scientists may not fully understand the specific environmental conditions of early Earth, which could differ significantly from those in the experimental setup.
Step 2
Give three reasons why the percentage of carbon dioxide in the Earth’s atmosphere today is less than the percentage of carbon dioxide in the Earth’s early atmosphere.
Answer
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Carbon dioxide is used by plants and algae for photosynthesis, which reduces its concentration in the atmosphere as it is absorbed and converted into organic matter.
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Carbon dioxide is dissolved in oceans, where it can form calcium carbonate and reduce its levels in the atmosphere.
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Carbon dioxide is locked up in sedimentary rocks and fossil fuels over geological timescales, effectively sequestering it away from the atmosphere.
Step 4
Step 5
Step 6
Explain why each stage is needed in the production of steel.
Answer
Stage 1 involves passing oxygen into molten cast iron to react with carbon, reducing the carbon content and transforming the iron from brittle cast iron to a more malleable form. Stage 2 adds small amounts of other metals to create an alloy with specific properties, ensuring the steel has the required strength and ductility for various applications.