State — 2 marks
A scientist is studying the composition of Earth's atmosphere and the role of different gases in trapping heat. She measures the concentration of various gases and their ability to absorb infrared radiation emitted from Earth's surface.
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State the name of two greenhouse gases present in Earth's atmosphere.
[2 marks]
Show mark scheme
- 1 mark: Any two of: carbon dioxide / CO₂, methane / CH₄, water vapour, nitrous oxide / N₂O, ozone
- Acceptable answers: greenhouse gases must be named correctly (alternative names or formulas accepted)
Define — 2 marks
Scientists studying atmospheric composition have identified several gases that trap heat in Earth's atmosphere. These gases are released through human activities such as burning fossil fuels and agriculture. Understanding what these gases are and how they work is important for addressing climate change.
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Define what is meant by a greenhouse gas.
[2 marks]
Show mark scheme
- A gas that absorbs (or traps) infrared radiation / heat energy (1 mark)
- in the Earth's atmosphere / preventing it from escaping to space (1 mark)
State — 2 marks
A scientist is studying the atmosphere and the factors that contribute to global warming. She is investigating how certain gases trap heat in the atmosphere and prevent it from escaping into space.
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(a) State the name of one greenhouse gas other than carbon dioxide.
[1 mark]
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(b) State one human activity that increases the concentration of greenhouse gases in the atmosphere.
[1 mark]
Show mark scheme
- (a) Methane (CH₄)
- (a) Nitrous oxide (N₂O)
- (a) Water vapour
- (a) Ozone
- (b) Burning fossil fuels / combustion of fossil fuels
- (b) Deforestation
- (b) Agriculture / livestock farming
- (b) Industrial processes
- (b) Cement production
- (b) Vehicle emissions / transport
Suggest — 3 marks
A renewable energy company is planning to replace a coal-fired power station with a solar farm. The local council is concerned about the environmental impact of this transition and wants to understand how this change will affect greenhouse gas emissions in the region.
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(a) Suggest why burning coal in the power station contributes to climate change.
[1 mark]
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(b) Suggest two ways in which replacing the coal-fired power station with a solar farm could reduce greenhouse gas emissions.
[2 marks]
Show mark scheme
- (a) Burning coal releases carbon dioxide / CO₂ (a greenhouse gas) into the atmosphere
- (a) Carbon dioxide / greenhouse gases trap heat / thermal energy in the atmosphere
- (a) This causes the greenhouse effect / global warming / climate change
- (b) Solar farms do not burn fossil fuels so they do not release carbon dioxide / CO₂
- (b) Solar energy is renewable so it does not produce greenhouse gases during operation
- (b) Fewer / no fossil fuels are needed for electricity generation, reducing overall emissions
- (b) Solar power reduces dependence on coal which is a non-renewable fossil fuel
Define — 5 marks
A science class is studying how human activities are contributing to climate change. Their teacher shows them data about increasing concentrations of carbon dioxide and methane in the atmosphere over the past 50 years. The students are asked to explain the role of these gases in warming the Earth.
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(a) Define what is meant by a greenhouse gas.
[2 marks]
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(b) Define the term 'global warming'.
[2 marks]
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(c) Name two greenhouse gases other than carbon dioxide.
[1 mark]
Show mark scheme
- (a) A gas that absorbs (infrared) radiation / heat (1 mark)
- (a) Prevents heat from escaping the Earth's atmosphere / traps heat (1 mark)
- (b) An increase in the average temperature of the Earth / atmosphere (1 mark)
- (b) Caused by greenhouse gases trapping heat / increasing concentration of greenhouse gases (1 mark)
- (c) Any two from: methane, nitrous oxide, water vapour, ozone (1 mark for both correct)
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