Chemistry Hydrocarbons&Fractional distillation mindmap
- Created by: smithy3107
- Created on: 19-03-20 12:00
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- Hydrocarbons and fractional distillation
- A hydrocarbon is any compound that is formed from carbon and hydrogen atoms only.
- Alkanes are the simplest type of hydrocarbon you can get.
- They have the general formula CnH2n+2
- Alkanes are saturated compounds meaning that each carbon atom forms four single covalent bonds
- The first four alkanes are methane CH4, ethane C2H6, propane C3H8 and butane C4H10.
- Hydrocarbon properties change as the chain gets longer.
- The shorter the carbon chain, the more runny a hydrocarbon is- the less viscous it is.
- Hydrocarbons with shorter chains are also more volatile, meaning they have lower boiling points.
- The shorter the carbon chain the more flammable the hydrocarbon is.
- The properties of hydrocarbons affect how they are used for fuels.
- Complete combustion occurs when there is plenty of oxygen.
- The complete combustion of any hydrocarbon in oxygen releases lots of energy.
- hydrocarbon+oxygen-->carbon dioxide+water +(energy)
- Hydrocarbons are used as fuels due to the amount of energy released when they completely combust.
- Fractional distillation is used to separate the useful hydrocarbons from crude oil.
- Crude oil is a fossil fuel that is formed from the remains of plants and animals that dies millions of years ago. It can be drilled up from rocks where it is found.
- The method of fractional distillation-
- 1. The oil is heated until most of it has turned into gas, and the gases enter the fractionating column.
- 2. In the column there is a temperature gradient (hot at the bottom and cooler as you go up).
- 3. The longer hydrocarbons have high boiling points, so they condense and drain out of the column near the bottom
- 4. The crude oil is separated out into different fractions. each fraction contains hydrocarbons that have similar carbon atoms as they have similar boiling points.
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