AQA GCSE Chemistry key terms

A polymer containing many ester links in its chain.

A large molecule made from many smaller units joined in a chain.

A polymer chain formed when many amino-acid monomers join by condensation polymerisation.

The side of a reversible reaction favoured at equilibrium, indicated by the relative amounts of reactants and products.

A positively charged particle formed when an atom loses one or more electrons.

Water that is safe to drink and has sufficiently low levels of dissolved salts and microbes.

The difference in electrical energy transferred per unit charge between two points.

An insoluble solid that forms when two solutions react.

To form a solid from substances in a solution; early oceans produced solid carbonates that settled as sediments.

The force exerted per unit area; increasing the pressure of reacting gases packs them into a smaller volume.

A substance formed during a chemical reaction.

A feature of a material or product, such as its colour, viscosity, strength, effectiveness or shelf life.

A naturally occurring polymer made from amino acids; different amino acids can occur within the same chain.

A positively charged particle found in an atom's nucleus.

A chemical change in which a hydrogen ion, $H^+$, moves from one reacting particle to another.

A single element or a single compound that is not mixed with any other substance.

A single substance containing no other elements or compounds mixed with it; chemically pure water contains only H₂O.

Analysis that establishes which substance or substances are present.

A test that identifies a substance from an observation such as a colour change, gas or precipitate, rather than measuring how much is present.

Analysis that measures how much of a substance is present, such as its concentration.

Numerical information obtained by counting or measurement.

The transfer of energy by electromagnetic waves.

The difference between the highest and lowest retained measurements in a set.

Able to produce a result quickly.

How quickly a reactant is used or a product is formed, expressed as a change in quantity per unit time.

The substances obtained and processed to make a product.

A starting substance that is changed during a chemical reaction.