A gram(g) is a metric unit of mass and was formally defined as the absolute weight of a volume of pure water equal to the cube of the hundredth part of a meter, and at the temperature of melting ice.
While a mole is the unit of measurement for amount of substance in the International System of Units.
Formula to convert grams to moles.
To convert g to moles, we divide the g by the molecular weight of the substance.
Moles = Grams ÷ Molecular Weight
Convert 20 grams of sodium to moles.
From the periodic table, we are told that the molecular weight of Na is 23grams, therefore, we will divide 20 g by 23 g.
= 20 ÷ 23
= 0.87 moles.