Avogadro's law (sometimes referred to as
Avogadro's hypothesis or
Avogadro's principle) is an experimental
gas law relating
volume of a gas to the
amount of substance of gas present. A modern statement of Avogadro's law is:
Avogadro's law states that, "equal volumes of all gases, at the same temperature and pressure, have the same number of molecules". For a given mass of an ideal gas, the volume and amount (moles) of the gas are directly proportional if the temperature and pressure are constant.
which can be written as:
or