Glossary of terms	Click a blue link in the document above to display definitions. Adjust the size of this window by dragging its top.
Aqueous solution	A solution in water.
Atom economy (also called atom utilisation)	A measure of the percentage of the starting materials that actually ends up in the useful products.
Biodegradability	A substance is biodegradable if it breaks down naturally in the environment by the action of enzymes, for example
Carboxylic acid	An organic compound containing the functional group –COOH.
Chemical synthesis	The process by which one chemical is made from another.
Dipole	A bond in which the positive and negative electric charges are not evenly distributed is said to have a dipole.
Dipole moment	A molecule in which the positive and negative electric charges are not evenly distributed is said to have a dipole moment.
Electronegative	This describes an atom that tends to attract electrons towards it.
Enantiomer	One of a pair of optical (mirror image) isomers.
Enzymes	Highly efficient protein-based catalysts found in living systems.
Fraction	A mixture of liquids with similar boiling points collected as a product of distillation.
Landfill	A method of disposing of waste by burying it underground.
Limiting reactant	The reactant that is in short supply in a chemical reaction. It is this reactant that governs the theoretical maximum amount of product that can be made from the reaction.
Racemic mixture	A mixture containing equal amounts of two optical isomers of the same substance.
Renewable resources	Resources, such as crops, that can regularly be replaced.
Selectivity	The degree to which a particular reaction produces the desired product rather than competing side-products.
Solute	A substance that dissolves in another substance (the solvent).
Solvent	A liquid that dissolves another substance (the solute).
Sublimation	This describes the process by which a solid turns directly into a gas without passing through a liquid state.
Surfactant	A substance which, when added to a solvent, improves its cleaning power by reducing its surface tension.
Surface tension	The ‘skin’ effect on the surface of a liquid caused by the molecules in the surface layer attracting one another.
Yield (of a chemical reaction)	The number of moles obtained of a specified product divided by the maximum number of moles that could have been obtained if all the reactant had been converted to product. It is usually expressed as a percentage.