Question

Define molecular formula and empirical formula. What are the similarities and differences between the empirical formula and molecular formula of a compound?

Answer 1

Explanation:

Molecular formula is the chemical formula which depicts the actual number of atoms of each element present in the compound.  

Empirical formula is the simplest chemical formula which depicts the whole number of atoms of each element present in the compound.  

In both the formulas, the nature of atoms remains the same but the number differs.

For Example: The molecular formula of oxalic acid is $C_2H_2H_4$ but the empirical formula of oxalic acid is $CHO_2$

To calculate the molecular formula, we need to find the valency which is multiplied by each element to get the molecular formula.

The equation used to calculate the valency is:

$n=\frac{\text{Molecular mass}}{\text{Empirical mass}}$

The empirical mass can be calculated from empirical formula and molar mass must be known.