Periodic Table of Elements

Avagadro's law

Avogadro's law is a principle stated by the Italian chemist Amedeo Avogadro (1776-1856) in 1811.

The avagadro's law states that under equal conditions of temperature and pressure, equal volumes of gases contain an equal number of molecules.

Avogadro's number is 6.022 * 10 23. This means that 12 grams of carbon-12 contains 6.022 * 10 23 carbon-12 atoms.

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.

The avagadro's law is expressed as: V n or V n = k
V is the volume of the gas.
n is the amount of substance of the gas (measured in moles).
k is a constant.

Because the formula is equal to a constant, Avagadro's law can be rewritten as: V1 n1 = V2 n2

Example 1:
How many moles are there in one atom?

No. of moles= 1atom 6.022x1023atoms/mole = 1.66x10-24moles