GCSE Chemistry · Edexcel 1CH0 · Topic 8A
Fuels and crude oil
Key points
- Crude oil is a complex mixture of hydrocarbons (compounds of hydrogen and carbon only), formed over millions of years, so it is finite.
- Fractional distillation separates crude oil into fractions: gases, petrol, kerosene, diesel oil, fuel oil and bitumen. Shorter chains rise higher in the column.
- Short-chain fractions: lower boiling point, lower viscosity, easier to ignite.
- Alkanes form a homologous series with formula , similar reactions and gradually changing properties.
- Complete combustion: hydrocarbon + oxygen → carbon dioxide + water. Incomplete combustion produces carbon monoxide (toxic) and soot.
- Sulfur in fuels forms sulfur dioxide (acid rain); high engine temperatures form nitrogen oxides. Hydrogen is a cleaner fuel.
- Cracking uses heat and a catalyst to break long alkanes into shorter alkanes and alkenes, matching supply to demand.
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Crude oil is a thick, dark mixture of hydrocarbons, compounds containing hydrogen and carbon only. It formed over millions of years from the remains of ancient sea creatures, so it is a finite (non-renewable) resource. These notes cover how…
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