Impurities
Chemistry: Edexcel IGCSE, topic 15.1.7
Impurities
As well as containing hydrocarbons, fossil fuels contain impurities.
Sulfur impurities
- Sulfur is an impurity that is present in all fossil fuels.
- Sulfur oxidises when burned. This produces the toxic gas sulfur dioxide.
- If inhaled, sulfur dioxide can cause respiratory (breathing) problems.
- Sulfur dioxide can react with water to form sulfuric acid, which is a major component (part) of acid rain.
- Acid rain causes steel corrosion, the weathering of buildings and statues, and the death of insects, plants, and aquatic organisms.
Nitrogen oxides
- When hydrocarbons are burned in a confined space (e.g. in the internal combustion engines of cars), the high temperatures can cause nitrogen and oxygen to react.
- This leads to the formation of toxic nitrogen oxides.
- Nitrogen oxides can also contribute to acid rain.
Test yourself on Impurities
Which of these are true about sulfur and its different forms?
What causes nitrogen and oxygen to react when hydrocarbons are burned in a confined space?