AQA GCSE Chemistry key terms

Rain made more acidic when pollutant gases, including sulfur dioxide and oxides of nitrogen, form acids in atmospheric water.

The minimum energy that reacting particles must have for a reaction to occur when they collide.

The measured amount of product actually obtained and collected in practice.

A reaction in which many unsaturated monomers join to form a polymer without producing another molecule.

A reaction in which atoms from another molecule join across a carbon–carbon double bond, forming a single carbon–carbon bond and one product.

Treatment in which microorganisms break down organic matter in the presence of oxygen.

An organic compound containing an –OH functional group attached to a carbon atom.

Photosynthetic organisms that commonly live in water; algae began producing oxygen long before plants evolved.

A soluble base that produces hydroxide ions, $OH^-(aq)$, in aqueous solution.

The reactive metals in the first column of the periodic table, whose atoms each have one electron in their outer shell.

A solution containing hydroxide ions, $OH^-(aq)$; it has a pH above 7.

A hydrocarbon whose carbon atoms are joined by single bonds only.

A hydrocarbon containing a carbon–carbon double bond, C=C.

The carbon–carbon double bond, C=C, that gives alkenes their characteristic reactions.

One of the different structural forms of an element, produced when its atoms are bonded or arranged differently.

A mixture of two or more elements, at least one of which is a metal, that has metallic properties.

An investigation in which positively charged alpha particles were directed at thin metal foil and their paths after passing through or being deflected were observed.

A functional group written as –NH₂ in an amino acid.

A compound of nitrogen and hydrogen with the formula NH₃, used to manufacture nitrogen-based fertilisers.

A compound containing the ammonium ion, NH₄⁺, together with a negative ion.

The quantity of a substance measured in moles, rather than its mass or volume.

The breakdown of organic matter by microorganisms without oxygen.

A substance that contains no water, especially no water of crystallisation.

A negatively charged ion formed when an atom gains one or more electrons.

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

A result that does not fit the pattern of the other results and may have arisen from an experimental problem.

An increase in the amount of greenhouse gases in the atmosphere caused by human activity.