Chemistry key terms

A cell whose chemical reactions can be reversed by supplying an external electrical current, allowing the cell to be used again.

Processing material from a used product to make a new product.

The processing of waste material so that it can be made into a new product.

Indicator paper that turns blue under alkaline conditions.

A reaction in which oxidation and reduction occur together because electrons are transferred between particles.

Using less material or fewer products in the first place, reducing demand for raw materials and energy.

A substance that removes oxygen from another substance and is itself oxidised.

Gain of electrons.

Data obtained from a known substance and used for comparison with an unknown sample.

The distinctive result produced by a known substance and used to help identify it.

A spectrum from a known substance, used to identify substances in an unknown sample by comparison.

A substance or result with known properties that is used for comparison with an unknown sample.

A trusted value for a known substance, used for comparison with an experimental result.

Planting trees to restore or establish forest, allowing growing trees to take in carbon dioxide by photosynthesis.

An ordered, repeating arrangement of particles in a solid.

The fibres or fragments held within a composite's matrix.

The proportion of a sample made up of a particular isotope, often expressed as a percentage.

The abundance-weighted mean mass of the atoms of an element compared with one-twelfth of the mass of a carbon-12 atom. It has no unit and is written $A_r$.

The weighted mean mass of the atoms of an element compared with one-twelfth of the mass of a carbon-12 atom.

The charge of a particle expressed by comparison with the magnitude of the charge on a proton.

The sum of the relative atomic masses of all the atoms represented by a chemical formula.

The sum of the relative atomic masses of all the atoms shown in a chemical formula.

A mass stated by comparison with an agreed reference rather than in kilograms.

The mass of a molecule compared with one-twelfth of the mass of a carbon-12 atom; it is found by adding the relative atomic masses of all the atoms in the formula.

The sum of the relative atomic masses of all the atoms represented in a molecular formula.

The relative mass of the particle being counted, found from the relative atomic masses of the atoms in its formula. It has no unit.

A comparative measure calculated as $1/t$ when every experiment reaches the same fixed endpoint.

A comparison of the sizes of two objects, normally made after expressing both measurements in the same unit.

A value that compares a particle's charge or mass with an agreed reference value rather than giving its absolute measurement.

A resource that is naturally replenished on a human timescale, provided it is not used faster than it is replaced.