How do you find moles

The equation for finding how many moles are in a substance is

moles = mass / relative formula mass,

where mass is measured in g.

The r. f. m. (relative formula mass) is found by adding together all of the atomic masses of the elements in a substance.

e. g. CO2 (carbon dioxide) has 1 atom of carbon and two atoms of oxygen.

The relative atomic mass of carbon is approximately 12.

The relative atomic mass of oxygen is approximately 16.

12 + (2 x 16) = 44

The r. f. m. of carbon dioxide is 44.

You would then divide the mass of the substance (how much there is of it) by its r. f. m. to find the mole number.