Key terms & definitions

Cooking food gently in liquid just below boiling point.

The buying or selling of positions in the Church.

Separating a solvent from a solution by boiling it and then cooling its vapour to collect the liquid.

A method in which a liquid is evaporated and then condensed so that it can be collected.

Separation in which a liquid is vaporised and its vapour is then cooled and condensed for collection, for example obtaining water from salt solution.

An arrangement of gears in which each shaft carries one gear; intermediate gears pass movement between the input and output.

Interest calculated on the original principal only, so the same amount of interest is added in each equal time period.

A single charged atom formed when an atom gains or loses electrons.

A substance made of separate, small molecules in which non-metal atoms are joined by covalent bonds.

A substance containing separate, relatively small molecules with covalent bonds within each molecule.

A substance consisting of separate, small molecules, with covalent bonds within each molecule and intermolecular forces between molecules.

A discrete group of atoms joined by strong covalent bonds.

A small group of atoms held together by covalent bonds, such as hydrogen, $\mathrm{H_2}$, or water, $\mathrm{H_2O}$.

A simplified representation in which small spheres stand for the atoms, ions or molecules in a substance.

A sample in which every member of the population has an equal chance of being selected.

A sample selected by chance so that every population member has an equal probability of selection and every possible sample of the required size is equally likely.

A sampling method in which members are selected by chance, with every member of the population having an equal probability of selection.

A sentence containing one main clause and no subordinate clauses. It can still contain descriptive phrases.

A skill involving few decisions and relatively little co-ordination or concentration, which is usually learned quickly.

A ratio obtained by dividing every part by the same common factor until the parts have no common factor greater than 1.

A small sugar molecule, such as glucose, that can be joined to others to make a larger carbohydrate.

Rewriting an expression in an equivalent but usually shorter or more useful form.

An algebraic expression written with no unnecessary factors or operations while keeping the same value.

An equivalent ratio written using the smallest convenient values, or in a form specified by the question such as $n:1$.

To rewrite an expression in a more compact form without changing its value.

Reducing a fraction by dividing its numerator and denominator by common factors until no common factor greater than 1 remains.

Writing a fraction in an equivalent form in which the numerator and denominator have no common factor greater than 1.

Remembrance of God, often practised through meditation on God’s Name.

A model of a real-world process used to generate data and investigate possible outcomes.

An on-screen test of a programmed routine that lets the user inspect its behaviour before running it on the physical system.