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This question is about the Earth's atmosphere - AQA - GCSE Chemistry Combined Science - Question 2 - 2018 - Paper 2
Question 2
This question is about the Earth's atmosphere. Carbon dioxide is a greenhouse gas. What is another greenhouse gas? Tick one box. Argon Methane Nitrogen Oxygen... show full transcript
Worked Solution & Example Answer:This question is about the Earth's atmosphere - AQA - GCSE Chemistry Combined Science - Question 2 - 2018 - Paper 2
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Step 3
Calculate the carbon footprint of one plastic bottle of mass 23.5 g.
Answer
To calculate the carbon footprint of one plastic bottle, we can use the ratio of the total carbon footprint to the total mass of plastic.
- Total carbon footprint for 4.1 kg = 6.0 kg of carbon dioxide.
- Carbon footprint per kg = ( \frac{6.0}{4.1} ) kg of carbon dioxide per kg of plastic.
- Carbon footprint for 0.0235 kg = ( \left( \frac{6.0}{4.1} \right) \times 0.0235 \approx 0.0344 ) kg of carbon dioxide.
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Step 5
Explain how the percentages of nitrogen, oxygen and carbon dioxide in the Earth's atmosphere today have changed from the Earth's early atmosphere.
Answer
Changes in Atmospheric Composition
Nitrogen
The percentage of nitrogen in Earth's atmosphere has increased due to:
- Volcanic eruptions that produced nitrogen.
- The conversion of ammonia into nitrogen by bacteria.
Oxygen
Oxygen levels have increased primarily because:
- Algae and plants produce oxygen through photosynthesis.
Carbon Dioxide
The proportion of carbon dioxide has decreased because:
- Carbon dioxide was absorbed by oceans and locked in sediment.
- The formation of fossil fuels, such as crude oil and natural gas, has resulted from the decomposition of organic materials.