Molecular formula is a chemical formula that gives the total number of atoms of each element in each molecule of a substance.
It expresses information about the proportions of atoms that constitute a particular chemical compound, using a single line of chemical element symbols and numbers.
Formula to calculate molecular formula.
- Divide the molar mass of the compound by the empirical formula molar mass.
- Multiply all the subscripts in the empirical formula by the whole number found in step 2
Lets consider water which has a molar mass of 18g/mol and its empirical formula molar mass is H2O.
For water, the empirical formula is the same as the molecular formula.
This is because, when you divide the empirical and the molar mass of water you get 1. When you multiply 1 with the subscripts you still get the same answer.