OCR F321 and F322 Glossary

Chemistry Glossary | F321

Isotopes - Atoms of an element with different numbers of neutrons and different masses

Relative isotopic mass – Average mass of a particular isotope relative to 1/12^th of the mass of a carbon-12 atom

Relative atomic mass – Average mass of an atom relative to 1/12^th of the mass of a carbon-12 atom

Amount of substance – The quantity whose unit is a mole

Mole – Unit for amount of substance

Avogadro constant – The number of particles per mole (6.02 x 10²³)

Empirical formula – The simplest whole number ratio of atoms of each element in a compound

Molecular formula – The actual number of atoms of each element in a molecule

Acid – Proton donor (H⁺ donor)        

Base – Proton acceptor (H⁺ acceptor)

Salt – Produced when the H⁺ ion of an acid is replaced by a metal ion

Anhydrous – A substance containing no water molecules

Hydrated – Crystalline and containing water molecules

Water of crystallisation – Water molecules that form an essential part of the crystalline structure of a compound

Oxidation – Increase in oxidation number or Loss of electrons

Reduction - Decrease In oxidation number or Gain of electrons

First ionisation energy – The energy required to remove one electron from each atom one…