OCR GCSE Chemistry A key terms

The amount of exposed surface available for contact with another substance.

An estimate of a value beyond the measured range of data.

A multiplicative comparison found by dividing one value by another; for example, a factor of 2 means twice as large.

Rewriting an expression as a product, usually by taking out a common factor.

A test in which only the independent variable is changed while relevant control variables are kept constant.

A group of organic compounds with related structures and similar chemical properties.

A raw material used in an industrial process to make other substances or products.

A substance added to soil to replace mineral nutrients needed for plant growth.

The liquid that passes through filter paper during filtration.

A method of separating an insoluble solid from a liquid by passing the mixture through a filter.

A resource with a limited supply that is depleted as it is used.

A consistent, defined observation used to stop timing, such as the moment a cross is no longer visible.

A test in which certain metal ions are identified from the characteristic colour produced when their compounds are heated in a flame.

A pull between particles which must be overcome or weakened for particles to separate during a change of state.

Pulling forces that tend to keep particles close together.

An equation that represents a relationship between two or more quantities.

A mixture designed as a useful product, with its components combined in carefully measured quantities to give required properties.

The simplest whole-number ratio of ions in an ionic compound.

The direction of a reversible reaction in which the starting reactants form products.

A group of compounds collected from crude oil whose molecules have similar boiling points.

The separation of a mixture of liquids into fractions according to differences in their boiling points.

A change of state from a liquid to a solid.

A cell that converts energy from a continuing supply of fuel and oxygen into electrical energy.

A hollow molecule made only of carbon atoms, arranged as a cage or tube.

A drawing of a molecule that shows every atom and every covalent bond, including bonds to hydrogen.

A group of atoms in a molecule that determines how it reacts, such as $-\mathrm{COOH}$, $-\mathrm{OH}$ or $-\mathrm{NH_2}$.

Coating iron or steel with zinc to protect it from corrosion.