AQA GCSE Chemistry contents

Unit 9 · Chemistry of the Atmosphere

Atmospheric Pollutants

2 min read · part of the full Exam Guide

Pollutants from burning fuels

  • Most fuels contain carbon and hydrogen, and some contain sulfur. Burning them is the major source of atmospheric pollutants
  • Products can include carbon dioxide, water vapour, carbon monoxide, sulfur dioxide, oxides of nitrogen, and particulates (solid carbon particles and unburned hydrocarbons)
Pollutant How it is produced
Carbon monoxide, CO incomplete combustion: not enough oxygen, so the carbon is only partly oxidised
Soot (carbon particles) incomplete combustion with even less oxygen; carbon is released unburned
Sulfur dioxide, SO2\text{SO}_2 sulfur impurities in the fuel are oxidised when it burns
Oxides of nitrogen, NOx\text{NO}_x nitrogen and oxygen from the air react at the high temperature inside an engine
  • To predict the products: complete combustion of a hydrocarbon gives carbon dioxide and water; with limited oxygen add carbon monoxide and carbon; if the fuel contains sulfur add sulfur dioxide; at engine temperatures add oxides of nitrogen

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In the full topic

  • Pollutants from burning fuels
  • Effects of pollutants
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