AQA GCSE Chemistry key terms

The trapping of carbon dioxide from power generation or industry followed by its long-term storage, usually underground.

The total amount of carbon dioxide and other greenhouse gases emitted over the full life cycle of a product, service or event.

A colourless, odourless and toxic gas that may be released when a carbon-containing fuel burns incompletely.

A long, hollow, cylindrical fullerene made of bonded carbon atoms.

Compensating for emissions by supporting activities that remove or prevent greenhouse-gas emissions elsewhere, such as reforestation.

The –COOH group that gives carboxylic acids their characteristic reactions.

A functional group written as –COOH in an amino acid.

A substance that increases the rate of a reaction without being used up.

The negative electrode in electrolysis, where positive ions gain electrons.

A positively charged ion formed when an atom loses one or more electrons.

A relationship in which a change in one factor produces a change in another.

A device in which reacting chemicals produce a potential difference and can transfer electrical energy around a circuit.

A hard, heat-resistant, non-metallic material made by shaping or forming raw material and then heating it.

A particle that carries electric charge through a substance, such as a mobile ion.

A combination of element symbols and numbers showing which elements a substance contains and their fixed proportions.

A process in which atoms are rearranged to form one or more new substances.

A one- or two-letter abbreviation used to represent an element and its atoms.

A greenish-yellow, toxic gas with the formula Cl₂.

The pattern of spots produced when substances have been separated by chromatography.

Separating dissolved substances because they travel at different speeds through a material with a moving solvent.

The long-term pattern of weather conditions in a region or across Earth.

A lasting change in climate patterns, including average temperature, rainfall and the frequency or intensity of extreme weather.

A factor that changes the Earth's energy balance and therefore tends to warm or cool the climate.

A simplified representation of the climate system used to investigate past changes or project possible future changes.

A system in which substances cannot enter or leave, so reactants and products cannot escape.

Particles with diameters from 2500 nm to 10,000 nm, often described as dust.

The number placed before a chemical formula in a balanced equation; for a gas, it shows the relative number of molecules of that substance.