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 breathing
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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 primarily due to increased photosynthesis by plants. As plants use carbon dioxide during photosynthesis to produce oxygen and glucose, they effectively reduce the concentration of carbon dioxide in the atmosphere. Additionally, the development of the oceans and increased weathering of rocks have played roles in this decline.
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 the burning of fossil fuels for energy, including coal, oil, and natural gas.
