Edexcel iGCSE Chemistry -2.13 Carbon Dioxide and Climate Change- Study Notes- New Syllabus
Edexcel iGCSE Chemistry -2.13 Carbon Dioxide and Climate Change- Study Notes- New syllabus
Edexcel iGCSE Chemistry -2.13 Carbon Dioxide and Climate Change- Study Notes -Edexcel iGCSE Chemistry – per latest Syllabus.
Key Concepts:
2.13 know that carbon dioxide is a greenhouse gas and that increasing amounts in the atmosphere may contribute to climate change
2.13 Carbon Dioxide as a Greenhouse Gas and Its Role in Climate Change
Carbon dioxide (\( \mathrm{CO_2} \)) is a greenhouse gas.
Greenhouse gases trap heat in the Earth’s atmosphere.
How the Greenhouse Effect Works
- Energy from the Sun reaches the Earth.
- The Earth absorbs energy and warms up.
- The Earth emits infrared radiation (heat).
- Carbon dioxide absorbs some of this infrared radiation.
- The heat is re-radiated back towards the Earth.
- This traps heat and increases global temperature.
This natural process is called the greenhouse effect.
Sources of Carbon Dioxide
- Combustion of fossil fuels:
\( \mathrm{C(s) + O_2(g) \rightarrow CO_2(g)} \)
- Respiration:
\( \mathrm{C_6H_{12}O_6(aq) + 6O_2(g) \rightarrow 6CO_2(g) + 6H_2O(l)} \)
- Deforestation (reduces carbon dioxide absorption by plants).
- Cement manufacture.
Why Increasing Levels Are a Problem
- More carbon dioxide traps more heat.
- Global temperatures rise.
- Ice caps may melt.
- Sea levels may rise.
- Weather patterns may become more extreme.
This contributes to climate change.
| Cause | Effect |
|---|---|
| Burning fossil fuels | Increases \( \mathrm{CO_2} \) levels |
| Increased \( \mathrm{CO_2} \) | More heat trapped |
| More heat trapped | Global warming |
| Global warming | Climate change |
Example 1 (Conceptual):
Why is carbon dioxide described as a greenhouse gas?
▶️ Answer/Explanation
It absorbs infrared radiation.
It traps heat in the atmosphere.
This increases the Earth’s temperature.
Example 2 (Application):
Explain why deforestation can contribute to climate change.
▶️ Answer/Explanation
Trees remove \( \mathrm{CO_2} \) during photosynthesis.
Fewer trees means less carbon dioxide is removed.
This increases greenhouse gas levels.
Example 3 (Hard):
Explain fully how increasing levels of carbon dioxide in the atmosphere may contribute to climate change.
▶️ Answer/Explanation
Carbon dioxide is a greenhouse gas.
It absorbs infrared radiation emitted from the Earth’s surface.
This prevents heat from escaping into space.
As the concentration of carbon dioxide increases, more heat is trapped.
This raises global temperatures.
Higher temperatures can melt polar ice caps.
This leads to rising sea levels and changes in climate patterns.