5 of the Chemistry glossary’s terms, each with the part of the syllabus where you first meet it.
Describes an elementary step in which a single particle breaks apart or rearranges (molecularity 1).
A mixture of indicators that shows a range of colours across the pH scale, used to estimate pH to about the nearest whole unit.
An electron that occupies an orbital on its own, without a second electron of opposite spin.
Describes a compound that contains at least one carbon–carbon double or triple bond, such as an alkene or alkyne.
An alkene whose two double-bonded carbon atoms carry different groups, such as propene, so that an adding molecule HX can give two different products.