OCR GCSE Chemistry B key terms

Two or more different substances together without being chemically bonded to one another.

The phase that moves through the stationary phase; in paper chromatography, it is the solvent.

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

The amount, in moles, of dissolved solute per cubic decimetre of solution.

The volume occupied by one mole of a gas at a specified temperature and pressure; at room temperature and pressure it is assumed to be 24 dm³ mol⁻¹.

The mass of one mole of a substance. Its value in g/mol is numerically equal to the substance's relative formula mass.

An amount of substance containing the Avogadro number of particles.

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

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

A particle consisting of a fixed number of atoms joined by covalent bonds.

The ratio of amounts of reacting substances, in moles, given by the coefficients in a balanced equation.

Changed into the liquid state by heating.

Describes a substance made of individual, unbonded atoms rather than molecules.

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

A small molecule that can join to others to form a polymer.

A calculation in which the result of one mathematical operation is used in a later operation.

A unit of length equal to one billionth of a metre: $1\text{ nm}=1 \times 10^{-9}\text{ m}$.

A unit of length equal to one billionth of a metre: $1\,\text{nm}=10^{-9}\,\text{m}$.

A structure between 1 nm and 100 nm in size.

The range of dimensions measured in nanometres; nanotechnology commonly deals with structures about 1–100 nm in size.

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

A two-dimensional arrangement of faces that can be folded to make a three-dimensional shape.

Neither acidic nor alkaline; a neutral aqueous solution has a pH of 7.

A reaction in which an acid and an alkali react to form a salt and water.

A solution with a pH of 7, which is neither acidic nor alkaline.

An uncharged subatomic particle found in the nucleus, with a relative mass of 1.

An alternative name for a Group 0 element, reflecting its very low chemical reactivity.