Edexcel GCSE Chemistry key terms

The amount of dissolved substance in a given volume of solution.

Titration results that are close enough to one another to be used together; in this practical, they are within 0.2 cm³.

Titre values that are sufficiently close to one another to be used in calculating a reliable mean.

The change of state from a gas to a liquid when a substance loses thermal energy.

Polymerisation in which monomers join and a small molecule, usually water, is eliminated when each new link forms.

The cooled part of a distillation apparatus where vapour turns back into liquid.

The principle that matter is not created or destroyed in a chemical reaction, so total mass remains constant when every reactant and product is included.

A final mass that no longer changes after repeated cycles of heating, cooling and weighing, indicating that the reaction is complete.

The unwanted presence of another substance in a sample or on the apparatus, which may produce a misleading result.

Manufacture in which reactants are supplied and product is removed continually while the process operates.

A comparison used to check whether an observed change was caused by the factor being investigated.

An action or feature that reduces the likelihood or severity of harm, such as using a smaller quantity, a safety screen or suitable eye protection.

A variable kept the same so that any change in the dependent variable can be linked fairly to the independent variable.

A salt made when copper(II) oxide reacts with sulfuric acid; it forms a blue solution and blue hydrated crystals.

A relationship in which two measured variables change in a connected pattern; it does not by itself establish that one causes the other.

The gradual destruction of a metal by chemical reactions with substances in its surroundings.

The ability of a material to withstand chemical attack by its surroundings.

Able to attack and damage materials or living tissue, including skin and eyes.

A strong bond formed when two atoms share a pair of electrons.

Bonding in which atoms are joined by shared pairs of electrons.

The breakdown of large hydrocarbon molecules into smaller molecules, some of which are alkenes.

A small heat-resistant container used to heat a solid strongly.

A naturally occurring fossil fuel that is a complex mixture of hydrocarbons.

The formation of solid crystals from a solution, usually after the solution has been concentrated and allowed to cool.

Information presented as measurements, counts or observations so that it can be examined and interpreted.

To remove the colour from a substance during a chemical change.

The chemical splitting of a compound into simpler substances.