It can be calculated using the formula: Percentage Composition=(Mass of the element in 1 mole of the compound/Molar mass of the compound)×100% The mass of one mole of a substance. The percentage ...

You can work out the molecular formula from the empirical formula, if you know the relative mass formula (M r) of the compound. Add up the atomic masses of the atoms in the empirical formula.

The formula mass of each reactant or product can be used to calculate the reacting masses. Calculate the mass of aluminium formed when 51 g of aluminium oxide are electrolysed. Firstly ...