Pollutants (Edexcel GCSE Chemistry Combined Science): Revision Notes
📚 Revision Notes
Pollutants
Pollutants from Incomplete Combustion
When fuels burn with insufficient oxygen, incomplete combustion occurs. This means the fuel doesn't completely turn into carbon dioxide and water. Instead, it produces harmful pollutants that can damage health and the environment.
Pollutants Produced by Incomplete Combustion
- Carbon Monoxide (CO):
- A toxic gas that can be deadly.
- It binds with red blood cells, preventing them from carrying oxygen around the body.
- This can lead to fainting, coma, or even death if inhaled in large amounts.
- Carbon (Soot):
- Tiny black particles of carbon are released into the air.
- Soot can settle on buildings, making them dirty and causing respiratory problems when inhaled.
- It also reduces air quality and contributes to pollution.
Sulfur Dioxide and Acid Rain
Sulphur dioxide (SO₂) is another harmful pollutant released when fossil fuels, which contain sulphur impurities, are burned.
- Sulfur dioxide reacts with water in clouds to form dilute sulfuric acid.
- This acid then falls to the ground as acid rain.
Effects of Acid Rain:
- Acidifies lakes, harming aquatic life.
- Damages plants, trees, and soil, affecting ecosystems.
- Erodes buildings made of limestone and other stones.
- Can cause metal structures to corrode.
Nitrogen Oxides (NOₓ)
Nitrogen oxides are formed when nitrogen in the air reacts with oxygen at high temperatures during combustion reactions, like in car engines.
Effects of Nitrogen Oxides:
- Contribute to the formation of acid rain.
- Lead to photochemical smog, which causes breathing problems, headaches, and tiredness.
- Harmful to both humans and the environment.
Hydrogen as a Fuel
Hydrogen can be used as a clean fuel alternative. When burned, it only produces water (H₂O), making it non-polluting. Unlike fossil fuels, hydrogen can be obtained from water through electrolysis, making it a renewable energy source.