8-Fuels and Earth Science

Acid Rain

Rain that is acidic due to gases, such as sulfur dioxide, reacting with water vapour in the clouds. Sulfur dioxide is produced from the burning of fossil fuels which contain sulfur impurities.

Alkanes

The most common hydrocarbon found in crude oil. Alkanes have the general formula Cn H2n+2.

Alkenes

Alkenes are hydrocarbons with a double bond between two of the carbon atom chain, causing them to be unsaturated. They have a formula of Cn H2n.

Catalytic Cracking

Long-chain hydrocarbons are heated to turn them into a gas. The vapour is then passed over a hot powdered aluminium oxide catalyst. The long chain molecules split apart on the surface of the catalyst.

Climate Change

A change in global climate patterns largely believed to be caused by the increase in concentration of carbon dioxide in the atmosphere.

Combustion

The burning of a substance in oxygen causing energy to be transferred to the surrounding as heat and light. During combustion, the carbon and hydrogen in the fuels are oxidised.

Complete Combustion

Combustion carried out in sufficient oxygen. Water and carbon dioxide are the only products of the complete combustion of a hydrocarbon.

Cracking

A process that involves breaking down larger hydrocarbons to produce smaller more useful molecules. Cracking can be done by catalytic cracking or steam cracking.

Crude Oil

A finite resource found in rocks. It is the remains of an ancient biomass consisting mainly of plankton that was buried in mud. Most of the compounds in crude oil are hydrocarbons.

Finite Resources

A resources which will one day run out.

Fossil Fuel

Natural fuels, such as coal and gas, formed in the past formed im the past from the remains of living organisms.

Fractional Distillation

A process used to separate mixtures of liquids. The liquids have different boiling points so can be separated into different fractions within a fractioning column.

General Formula

A chemical formula which applies to a class of compounds, representing the composition. Eg alkenes is CnH2n.

Greenhouse Effect

The increase in the temperature of the Earth’s atmosphere due to the greenhouse gases in the atmosphere trapping infra-red radiation from the surface.

Greenhouse Gases

Gases in the atmosphere which maintain temperatures on Earth high enough to support life. Eg water vapour, carbon dioxide and methane.

Homologous Series

A series of compounds with the same functional group and similar chemical properties.

Hydrocarbons

Compounds that are made up of hydrogen and carbon atoms only.

Incomplete Combustion

Combustion which is carried out with insufficient amount of oxygen. Can lead to the production of toxic carbon monoxide and carbon particulates.

Non-Renewable Energy

An energy resource which is finite. Eg. methane, petrol and diesel.

Particulates

Polluting particles which cause global dimming and health problems for humans. Soot is a product of incomplete combustion.

Photosynthesis

A reaction which occurs in plants and algae which led to the production of oxygen and decrease in carbon dioxide in the early atmosphere.

Pollutants

A substance introduced to the environment which has an undesired effect.

Steam Cracking

Long-chain hydrocarbons are heated to turn them into a gas. The hydrocarbon vapour is then mixed with steam and heated to a very high temperature which causes them to split into smaller molecules.