Monday, 26 January 2015

Avogadro's number


Avogadro's number, corresponds to the number of elementary particles, atoms or molecules in a mole of substance.

The value of Avogadro's number can be achieved experimentally with measurements based on many different phenomena, for example on the kinetic theory of gases, the diffusion of light in the atmosphere, on radioactivity, on electrolysis. Its value corresponds to 6.022 • 1023 particles / mol.
one mole of any Essentially this always contains 6.022 1023 particles, whether they are atoms, molecules or ions.

Avogadro's number represents the number of entities contained in the unit mole.
For example:

One mole of K + ions corresponds to 6.022 1023 K + ions;

One mole of Fe atoms corresponds to 6.022 • 1023 atoms Fe

One mole of electrons corresponds to 6.022 electrons 1023

Avogadro's number, No is the proportionality constant which allows to determine, note the chemical amount n, the number N of particles contained in a sample through the following relation:

N= No n
n = N/No

in which:

N = number of particles
No = Avogadro's number = 6.022 • 1023 particles / mol
n = number of moles (mol)

Conversely, knowing the number N of particles contained in a sample, it is possible, through the inverse formula, determine the value of the chemical amount n.