Avogadro's law
Avogadro's law 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 of the gas are directly proportional if the temperature and pressure are constant. which can be written as: or where:
V is the volume of the gas
n is the amount of substance of the gas.
k is a constant equal to RT/P, where R is the universal gas constant, T is the Kelvin temperature, and P is the pressure. As temperature and pressure are constant, RT/P is also constant and represented as
k. This is derived from the ideal gas law. This law explains how, under the same condition of temperature and pressure, equal volumes of all gases contain the same number of molecules.