Complete the sentence by putting a cross (X) in the box next to your answer - Edexcel - GCSE Chemistry - Question 2 - 2015 - Paper 1
Question 2
Complete the sentence by putting a cross (X) in the box next to your answer.
The Earth’s earliest atmosphere is thought to have been formed by:
A animals breathin... show full transcript
Worked Solution & Example Answer:Complete the sentence by putting a cross (X) in the box next to your answer - Edexcel - GCSE Chemistry - Question 2 - 2015 - Paper 1
Step 1
Complete the sentence by putting a cross (X) in the box next to your answer.
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Answer
The Earth's earliest atmosphere is thought to have been formed by D gases from volcanoes.
Step 2
Complete the sentence by putting a cross (X) in the box next to your answer.
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Answer
The percentage of carbon dioxide in the Earth's atmosphere today is C 21%.
Step 3
Write the formula of a molecule of carbon dioxide.
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Answer
The formula of a molecule of carbon dioxide is CO₂.
Step 4
Explain what has caused the amount of carbon dioxide in the atmosphere to decrease.
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Answer
The amount of carbon dioxide in the atmosphere has decreased due to processes such as photosynthesis, where plants absorb carbon dioxide and release oxygen, and the formation of carbon sinks in the oceans and soil which store carbon.
Step 5
State one human activity that increases the amount of carbon dioxide in the atmosphere today.
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Answer
One human activity that increases the amount of carbon dioxide in the atmosphere today is burning fossil fuels for energy.
