AQA A Level Chemistry - Amount of Substance

Definitions for preliminary test

Relative atomic mass

the weighted mean mass of an atom of an element relative to 1/12 the mass of a carbon-12 atom

Relative molecular mass

the weighted mean mass of a molecule relative to 1/12 the mass of a carbon-12 atom

Mole

amount of substance that contains 6.022 × 10²³ particles

Avogadro’s number / constant

the number of atoms in 12g of carbon-12, which is 6.022 × 10²³

Empirical formula

the simplest whole number ratio of atoms of each element in a molecule

Molecular formula

the actual number of atoms of each element in a molecule

Boyle’s law

the product of pressure and volume is constant as long as the temperature remains constant

Charle’s law

the volume is proportional to the temperature as long as the pressure remains constant

Gay-Lussac’s law

the pressure is proportional to the temperature as long as the volume remains constant