Question

How do empirical formulas and molecular formulas differ?

Answer 1

The simplest formula of compound is called an empirical formula whereas the molecular formula of compound is one which expresses the actual number of each atom in its molecule. In chemical formulas there are abbreviations for each compound and to denote formulation and amount there are terms described as empirical and molecular for mole.

Complete step by step answer:
Empirical formula for molecules is the simplest formula which represents the ratio of atoms in molecules at lowest terms. Empirical formula can be obtain by dividing molecular formula with their lowest common denominator
Examples:.
Benzene ${{\text{C}}_{\text{6}}}{{\text{H}}_{\text{6}}}$ empirical formula $\text{CH}$
Water ${{\text{H}}_{\text{2}}}\text{O}$ empirical formula ${{\text{H}}_{\text{2}}}\text{O}$
Glucose ${{\text{C}}_{\text{6}}}{{\text{H}}_{\text{12}}}{{\text{O}}_{\text{6}}}$ empirical formula $\text{C}{{\text{H}}_{\text{2}}}\text{O}$
Molecular formulas are the true formula of compounds which expresses the actual number of all kinds of atoms present in molecules.

Empirical formula	Molecular formula
Simplest form of expressing the elemental composition of a compound.	Actual representation of expressing the elemental composition of a compound.
Derived first from the weight percentages of the element present in a compound.	Related to the total weight of the compound.
Contains the most simplified ratio of the moles of elements in the compound.	Needs to be the multiple of the empirical formula.
It is not often used in reaction schemes.	It is commonly used in reactions and other chemical recordings.

For example: In glucose ${{\text{C}}_{\text{6}}}{{\text{H}}_{\text{12}}}{{\text{O}}_{\text{6}}}$ , there are $6$atoms of carbon, $12$atoms of hydrogen and $6$ atoms of oxygen.
How to found molecular formula from empirical formula:
Molecular formula $=n\times \text{Empirical formula}$
$n=\dfrac{\text{Molecular formula mass (molar mass)}}{\text{Empirical formula mass}}$

Note: Empirical and molecular formula is almost some the only difference between them are empirical formulas generally show what elements are present in a molecule. The molecular formula also shows the actual number of atoms of the element present in the compound.