How does Avogadro’s law relate gas volume to the number of moles?

Avogadro’s law states that, under the same conditions of temperature and pressure, equal volumes of different gases contain an equal number of molecules.21

Because the number of molecules in a substance is directly proportional to the amount of the substance measured in moles, this law implies that the volume of a gas is directly proportional to the number of moles of that gas, provided the temperature and pressure remain constant.21

For example, at standard temperature and pressure (0 °C and 1 atmosphere), one mole of any ideal gas occupies a volume of approximately 22.4 litres. This relationship is a fundamental concept in understanding the behavior of gases and was instrumental in the development of modern chemistry.21