Chemistry key terms

A simplified representation of a system used to explain it or predict what might happen.

Concentration expressed as the number of moles of solute in one cubic decimetre of solution.

The volume occupied by one mole of a gas at specified temperature and pressure. At RTP it is $24\,\text{dm}^3\text{/mol}$.

The mass of one mole of a substance, measured in grams per mole ($\mathrm{g\,mol^{-1}}$).

The volume occupied by one mole of a gas at a stated temperature and pressure.

The amount of substance measured in mol; balanced-equation coefficients give ratios between amounts in moles.

A formula that shows the actual number of atoms of each element in one molecule.

An ion formed from a whole molecule without its breaking into smaller fragments.

The three-dimensional arrangement of atoms bonded together in a molecule.

A structure with spaces of a suitable size that allow some particles through while excluding others.

A group of atoms joined by covalent bonds that exists as a separate unit.

The amount of substance containing a specified number of particles; it is not a unit of mass.

The relative amounts in moles of the substances taking part in a reaction.

Melted and in the liquid state.

Existing as individual atoms rather than as molecules containing two or more bonded atoms.

The use of equipment or observations to follow how a chemical reaction changes or progresses.

A layer of molecules that is one molecule thick.

A small molecule that can join to other monomer molecules to form a polymer.

A number written before a chemical formula that multiplies every atom in that formula.

A calculation that uses several linked stages, with the output from one stage becoming the input to the next.

A unit of length equal to one billionth of a metre: $1\ \text{nm}=1\times10^{-9}\ \text{m}$.

A unit of length equal to one billionth of a metre: $1\ \text{nm}=1\times10^{-9}\ \text{m}$.

A structure between 1 nm and 100 nm in size, typically containing of the order of a few hundred atoms.

A material made from, or containing, particles between 1 nm and 100 nm in size.

The range of dimensions measured in nanometres, usually referring to dimensions from about 1 nm to 100 nm.

The study and use of structures whose dimensions are between 1 nm and 100 nm.

The use and control of structures that are approximately 1–100 nm in size.

A fossil fuel consisting mainly of methane, with smaller quantities of other gases.

An organic compound described as natural because its source in that context is an organism or another natural process; the same compound may also be synthesised.

A substance or source of energy obtained from the Earth, oceans or atmosphere and used by humans.