Edexcel GCSE Chemistry key terms

A conclusion reached from evidence rather than from direct observation.

Does not dissolve to any significant extent in water under the conditions being considered.

A substance that does not dissolve, or dissolves only very slightly, in the reaction mixture.

The rate of reaction at one particular moment, found from the gradient of a tangent to a curve.

A method that uses an instrument to measure a property of a sample and provide data for chemical analysis.

A measure of the strength of detected radiation, usually shown on the vertical axis of a spectrum.

An attraction acting between separate molecules; it is much weaker than the covalent bonds within the molecules.

Forces of attraction between separate molecules.

An estimate made between known data values, within the measured range.

A charged atom or group of atoms formed by gaining or losing electrons.

The overall electrical charge produced by the difference between the numbers of protons and electrons.

A strong electrostatic attraction between oppositely charged ions in a giant lattice.

A compound made from oppositely charged ions, usually positive metal ions and negative non-metal ions.

An equation showing the particles that actually change in a reaction, with unchanged spectator ions omitted.

A substance made from oppositely charged ions held in a giant lattice by strong electrostatic attractions.

Compounds with the same molecular formula but different arrangements of atoms.

An atom of an element that has the same number of protons as other atoms of that element but a different number of neutrons.

Atoms of the same element that have the same number of protons but different numbers of neutrons.

The proportion of a sample made up of a particular isotope.

The energy a particle has because it is moving or vibrating.

A waste-disposal site where rubbish is buried or stored.

A regular, repeating three-dimensional arrangement of particles.

The principle that atoms are not created or destroyed in a chemical reaction, so the total mass of all reactants equals the total mass of all products.

A solution containing metal ions that have been dissolved out of an ore or metal-rich material.

A prediction rule: when conditions affecting an equilibrium change, the position shifts in a direction that opposes the change.

A study of a product’s environmental effects from obtaining its raw materials through manufacture and use to its eventual disposal.

A clear solution that turns milky in the presence of carbon dioxide.