Burning coal in a power station produces several atmospheric pollutants. Explain how two different pollutants produced by the burning of coal cause environmental problems.
Written & reviewed by James Millett — Biology (Imperial College London), PGCE Science (University of Cambridge).
Coal is a fossil fuel used in power stations to generate electricity. It contains carbon, hydrogen and sulfur impurities. When coal burns, it undergoes combustion in oxygen.
Model answer (5 marks)
1. Incomplete combustion of coal releases carbon monoxide (CO) and fine carbon particulates (soot). 2. CO is poisonous; it binds haemoglobin more strongly than oxygen, reducing oxygen delivery to tissues and causing headaches, dizziness and, in high concentrations, death. 3. Soot particles scatter sunlight, contributing to global dimming and can be inhaled, causing respiratory irritation and cardiovascular problems. 4. Sulphur impurities in coal oxidise to sulphur dioxide (SO₂). 5. SO₂ dissolves in atmospheric water vapour to form sulphuric acid, producing acid rain that acidifies soils and lakes, harms aquatic life, and corrodes buildings and statues.
Examiner tips
- Use the exact terms CO, soot, SO₂, acid rain; link each pollutant to a specific environmental or health effect; keep answer concise and structured to match the 5 marks.
- Show cause–effect chain: combustion → pollutant → effect.
- Include both human health and ecological impacts to cover all points.
Common mistakes
- Confusing CO with CO₂; failing to mention both CO and soot; not linking SO₂ to acid rain or omitting the damage caused by acid rain.
Mark scheme (5 marks)
- Incomplete combustion of coal produces carbon monoxide / carbon particulates (soot)
- Carbon monoxide is toxic / harmful to human health OR carbon particulates cause global dimming / health problems
- Sulfur impurities in coal burn to produce sulfur dioxide
- Sulfur dioxide reacts with water vapour in clouds to form acid rain
- Acid rain damages ecosystems / kills trees / acidifies lakes / damages buildings / statues
Key terms in this question
Related
- All Edexcel A-Level Chemistry (9CH0) revision notes →
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