What do you understand by formula unit mass and molecular mass? What is the difference between the two? [3 MARKS]

Definition: 2 Marks
Difference: 1 Mark

A formula unit is the empirical formula of any ionic compound which is used as an independent entity for stoichiometric calculations. It is the lowest whole number ratio of ions represented in an ionic compound.
Molecular mass or molecular weight is the mass of a molecule. It is calculated as the sum of the atomic mass of each constituent atom multiplied by the number of atoms of that element in the molecular formula.

The difference is that we use the word formula unit for those substances whose constituent particles are ions.