Fuels

• Sea creatures living millions of years ago • Fish die and their bodies fall to the bottom of the ocean • Pressure from water pushes them further down and together • Fossils of fish turn into crude oil

Hydrocarbons are molecules that only contain hydrogen and carbon atoms

Crude oil is a thick, black, viscous liquid that floats on water. It is composed of a very large mixture of hydrocarbons.

Crude oil is heated up until it turns into a gas. The gases enter a fractionating column, and the liquid part, bitumen, is drained off. The column is hot at the bottom and gets cooler as you go up. The hydrocarbons in crude oil have different boiling points, so they all condense and drain out at different places. You end up with the crude oil separated into different fractions.

Gases - heating and cooking Petrol - motor fuel Kerosene (paraffin) - jet fuel Diesel oil - fuel in cars and larger vehicles Fuel oil - fuel for large ships and some power stations Bitumen - road and roof surfacing

• Higher the boiling point • Less volatile it is • More viscous it is • Less flammable it is

An alkane is a hydrocarbon with only single carbon bonds. It has the general fomula CnH2n+2. The names of different alkanes all end in -ane. They are saturated, which means there are only single bonds.

There are only single bonds, which means they cannot open up and make more bonds.

Methane, ethane, propane, butane, pentane, hexane N/a, ethene, propene, butene, pentene, hexene

A group of chemicals with the same general formula and similar chemical structures and reactions/ chemical properties

An alkene is a hydrocarbon with a carbon-carbon double bond. It has the general formula CnH2n. The names of different alkenes all end in -ene. They are unsaturated, which means the double bond can open up, allowing the two carbon atoms to bond with other atoms.

Add bromine water to the alkane or alkene. Bromene water is orange, while alkanes/ alkenes are colourless. Alkanes will not change the colour of the water, while alkenes will make it colourless.

• Fossil fuels (coal and oil) are burned. Sulphur dioxide is released. • In cars nitrogen oxides are formed and released. • The gases react with sunlight and ozone and form sulphuric acid and nitric acid. • The acids dissolve in the moisture in the atmosphere. • They fall down with rain.

They can contaminate soil by making it too acidic, contaminate water by aluminium, which is activated by acid rain, slow down growth and kill plants and trees and damage buildings.

Use less energy Use more nuclear or renewable energy Burn coal that contains less sulphur Construct taller chimneys

Large metal boxes in cars made out of ceramic coated in a metal like platinum or palladium that convert harmful products of incomplete combustion into harmless substances by splitting up molecules. They convert nitrogen oxides into nitrogen and oxygen and carbon monoxide into carbon dioxide, and turn unburned hydrocarbons into carbon dioxide and water.

Complete combustion is the burning of an object with lots of oxygen present. It is seen in the blue flame of a gas hob and Bunsen burner. The general formula for the complete combustion of a hydrocarbon is: Hydrocarbon + oxygen –> carbon dioxide + water

Combustion that takes place when there is not enough oxygen for complete combustion. It produces less energy than complete combustion. The general formula for the incomplete combustion of a hydrocarbon is: Hydrocarbon + oxygen –> Carbon monoxide + carbon + water

Cracking is the splitting up of long chain saturated hydrocarbons (alkanes) into smaller unsaturated (alkenes) and alkane molecules.

It involves heat (400-700 degrees C), moderate pressure and a catalyst, aluminium oxide. It is an example of thermal decomposition. The molecules are heated until they turn to vapour and are mixed with a catalyst, which makes them break apart.

The supply of different hydrocarbons in crude oil is different to their demand, so you can crack some longer hydrocarbons you have too much of into smaller ones you have too little of in order to match the supply and demand.

A polymer is a substance of high average relative molecular mass made up of small repeating units called monomers.

Monomers with a double covalent bond are put under pressure with a catalyst and their double bonds open up and join together to form polymer chains.

Properties: flexible, electrical insulator, cheap Uses: Plastic bags, bottles, wire insulation