OCR GCSE Chemistry A key terms

Burning a substance in oxygen. Complete combustion of an organic compound produces carbon dioxide and water.

A material made by combining distinguishable materials, usually a reinforcement held in a matrix, to obtain a useful combination of properties.

A substance containing atoms of two or more elements chemically bonded in fixed proportions.

To force a substance into a smaller volume.

A solution containing a relatively large amount of dissolved acid per unit volume.

The amount of dissolved substance in a given volume of solution.

Results that agree closely enough to be used together when calculating a mean.

Titre results that are sufficiently close to one another to be treated as repeatable, according to the acceptance range being used.

The change of a gas into a liquid as it cools.

A reaction in which monomers join to form a polymer while a small molecule is released at each link formed.

A reaction in which molecules join while a small molecule is eliminated.

A condenser is apparatus that cools vapour so that it changes back into liquid.

A change of state from a gas to a liquid.

The pattern of which atoms are bonded directly to which other atoms in a structure.

The principle that atoms are rearranged rather than created or destroyed in an ordinary chemical reaction, so total mass is conserved in a closed system.

Unwanted material in a sample or on apparatus that can alter the observed result.

A manufacturing process in which reactants are supplied and product is removed continually.

A trial carried out without the substance being tested, used as a baseline for comparison.

Conditions kept consistent so that comparisons between experimental results are valid.

A quantity kept unchanged during an investigation so that the effect of the independent variable can be identified.

Factors kept constant so that any change in the result can be attributed to the independent variable.

The gradual deterioration of a metal as it reacts with substances in its surroundings.

Able to resist chemical attack by substances in the surroundings.

A strong bond formed when atoms share a pair of electrons.

The breaking of large hydrocarbon molecules into smaller, more useful molecules by strong heating.

The mass of crop harvested from a given area of land.

A naturally occurring mixture containing many different hydrocarbons.