# Crude oil contains hydrocarbons with sulfur impurities. When these hydrocarbons are burned as fuels, sulfur dioxide is produced as well as other combustion products. Explain how the combustion of hydrocarbons containing sulfur impurities, and the combustion of hydrocarbons in insufficient oxygen, each cause harm to the environment or human health.

> Pearson Edexcel International GCSE Chemistry (4CH1) — 4.2 Crude oil · Explain · 4 marks

> Crude oil fractions are widely used as fuels in transport and industry. The combustion of these fuels releases several pollutant gases and particles into the atmosphere.

## Mark scheme (4 marks)

1. Sulfur dioxide (from burning sulfur impurities) reacts with water vapour in clouds to form acid rain
2. Acid rain damages/kills trees, aquatic life, or corrodes buildings/metals (named harmful effect of acid rain)
3. Incomplete combustion (insufficient oxygen) produces carbon monoxide, which is toxic to humans
4. Incomplete combustion also produces carbon particulates, which cause global dimming or health problems such as respiratory problems in humans

## Key terms

- [impurities](https://www.gradenine.co.uk/glossary/impurities)
- [combustion](https://www.gradenine.co.uk/glossary/combustion)

## Related

- [Revision notes for Pearson Edexcel International GCSE Chemistry (4CH1)](https://www.gradenine.co.uk/learn)
- [How to answer "Explain" questions](https://www.gradenine.co.uk/tools/command-word-cheatsheet)
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Source: [GradeNine](https://www.gradenine.co.uk/q/crude-oil-contains-hydrocarbons-with-sulfur-c08c8f4c) · Published by Druglandscape Ltd.