Edexcel GCSE Chemistry key terms

A change between solid, liquid and gas in which the substance remains chemically the same.

Algebraically rewriting an equation so that a chosen variable is alone on one side.

The use of tests or measurements to identify substances or determine how much of a substance is present.

An attraction that holds atoms or ions together in a substance.

A cell whose stored reactants are used up as it supplies electrical energy; some chemical cells can be recharged.

A change in which one or more new substances are formed by a chemical reaction.

Symbols and numbers showing the elements present in a substance and the numbers or simplest ratio of their particles.

Describes a substance that is very unlikely to take part in chemical reactions.

Able to resist reaction with other substances.

Having the same chemical identity and composition as before.

A characteristic describing how a substance reacts to form other substances.

A one- or two-letter abbreviation for an element. Its first letter is capital and any second letter is lower-case.

A chemical used to identify another substance through an observable change.

Adding chlorine to water to kill harmful microorganisms.

The green pigment that absorbs the light energy needed for photosynthesis.

The pattern of spots produced when the soluble substances in a sample separate during chromatography.

The process of placing substances into groups by comparing characteristic properties or structures.

The average weather conditions of a place over a long period.

A long-term change in average climate conditions, such as temperature and rainfall patterns.

A system in which substances cannot enter or leave.

A number written before a chemical formula in an equation, showing the relative number of particles or moles involved.

The number of collisions between particles in a given time.

A model explaining reactions and their rates through collisions between reactant particles.

A chemical reaction in which a substance reacts with oxygen.

A reaction with enough oxygen in which a hydrocarbon produces carbon dioxide and water, giving out energy.

A material made by combining distinguishable materials so that their useful properties work together.

A pure substance whose atoms of two or more different elements are chemically bonded together.