Edexcel GCSE Chemistry key terms

A charged particle, such as an ion or electron, that is able to move through a substance and transfer charge.

An ion free to move through a liquid or solution and carry electrical charge.

The moving solvent that carries dissolved substances through the paper during chromatography.

The mass of one mole of a substance, measured in g mol⁻¹.

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

The amount of substance containing 6.02 × 10^23 specified particles, such as atoms, molecules, formula units or ions.

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

A discrete group of atoms held together by covalent bonds.

The numerical ratio between reacting amounts in moles, obtained from the coefficients in a balanced equation.

Melted by heating so that a substance is in the liquid state.

A layer of molecules that is one molecule thick.

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

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 particle with dimensions on the scale of approximately 1–100 nanometres.

A material containing particles on the nanometre scale.

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

The total charge found by combining all the positive and negative charges in a particle.

Having no overall electrical charge because the positive and negative charges balance.

A reaction between an acid and a base that produces a salt and water.

An uncharged particle found in an atom's nucleus.

An acid with the formula $\mathrm{HNO_3}$; in aqueous solution it supplies hydrogen ions and nitrate ions.

An oxide of nitrogen with the formula $\mathrm{NO_2}$ that can form when nitrogen monoxide reacts with more oxygen.

An oxide of nitrogen with the formula $\mathrm{NO}$, formed when nitrogen and oxygen react at very high temperatures.

An element in Group 0 of the periodic table; its atoms normally exist separately and it is a gas at room temperature.

A system that can exchange matter, such as a gas, with its surroundings.

A gas that does not burn.