Fuels
There are three main fuels that you need to be familiar with:
- Coal has been formed by the anaerobic decay of vegetation over millions of years. Anaerobic means in the absence of oxygen
- Natural gas is mainly methane
- Petroleum (or crude oil) is a complex mixture of hydrocarbons
Fractional distillation separates petroleum into more useful mixtures of hydrocarbons called fractions.
You need to know the different uses of each of the fractions.