Question

What is the significance of molecular formula?

Answer 1

Molecular formula: The symbolic representation of the composition of a molecule is known as a molecular formula.

• It indicates the number of atoms of different elements present in one molecule of the compound.
• Example: ${\mathrm{H}}_2\mathrm{O}$ is the molecular formula of water.

Significance of molecular formula:

• With the help of molecular formulas, all the elements present in a compound can be known. For example: for water, it tells us that water is made up of Hydrogen $\left(\mathrm{H}\right)$ and Oxygen $\left(\mathrm{O}\right)$.
• The number of atoms of each type of atom present in a compound can also be known. For example: in water, two atoms of hydrogen and one atom of oxygen are present.
• The relative molecular mass of a compound can be calculated by the addition of the relative atomic mass of atoms if the molecular formula is known. For example: The relative atomic mass of hydrogen and oxygen is $1\mathrm{amu}\mathrm{and}16\mathrm{amu}.$ So the relative molecular mass of water is $18\mathrm{amu}.$
• By knowing how many atoms of each type are present through molecular formula, the percentage composition of each element can be found in a compound. Example: in water, it tells that $2$ parts out of $18$ is hydrogen or $11.11\%$ is hydrogen and $1$ part is oxygen or $88.88\%$ is oxygen.