XSIQ
*

Chemistry - The mole concept

The mole concept

By definition one mole of any substance is the amount of that substance
containing as many defined particles - atoms, ions or molecules - as there
are atoms in 12 g of carbon-12.

In effect, the mole concept provides the link between the atomic scale and
conveniently measurable amounts.

Conveniently, the mass of one mole of any element is the relative atomic
mass (_A_r) of the element measured in grams.

These amounts are chemically equivalent in that they contain the same
numbers of identifying particles - Al atoms, H2O molecules, Na and Cl ions.


Because atoms of different elements have different masses, it is possible
to have exactly the same number of atoms or molecules, ie equal numbers of
moles, in a set of samples of different substances even though the samples
have significantly different masses.

Previous | Next