Chemistry key terms

A reaction in which substances in solution form an insoluble solid.

How closely repeated measurements agree with one another.

A conclusion about an unknown case based on an established pattern and relevant evidence.

A word part and symbol that scale a unit by a power of ten; for example, kilo (k) means $10^3$ and milli (m) means $10^{-3}$.

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

An alcohol in which the carbon attached to the –OH group is bonded to no more than one other carbon atom. It can be oxidised to a carboxylic acid.

Early, relatively simple photosynthetic organisms that used carbon dioxide and released oxygen.

A numbered, repeatable sequence of practical instructions stating what must be done, measured and recorded.

A diagram using boxes and arrows to show materials entering, moving through and leaving the stages of a process.

A substance formed by a chemical reaction.

The substances formed by a chemical reaction.

A flat representation of a three-dimensional object as viewed from a chosen direction.

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

The amount of one component compared with the amounts of the other components in a mixture.

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

A positively charged particle found in the nucleus; nuclear positive charge occurs in whole-number units of this particle’s charge.

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

A convenient measurement that represents another quantity; for a fixed reaction endpoint, $1/t$ can represent relative rate.

Indirect evidence used to estimate past conditions when direct measurements are unavailable, such as evidence from tree rings or gases trapped in ice cores.

An indirect measurement used to reconstruct past conditions when direct measurements are unavailable, such as evidence from ice cores or tree rings.

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.

The removal of other substances from a sample to increase its chemical purity.

Analysis that establishes which substance or substances are present.

Descriptive, non-numerical information about a property, such as whether a material is transparent or brittle.

A description or observation rather than a numerical measurement, such as a colour change or the formation of a precipitate.

A test substance that produces an observable result which helps to identify an unknown substance or product.

A test used to identify a substance from an observable result rather than by measuring how much is present.

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

A measurable amount associated with making, using or disposing of a product, such as its energy use, water use or mass of waste.