Question

Why it was necessary to measure the atomic mass?

Answer 1

Definition of atomic mass:

1. The mass of an atom of a chemical element is known as atomic mass of that element.
2. The atomic mass is expressed as atomic mass unit (u).

Measurement of atomic mass:

1. The atomic masses of all the atoms are measured by choosing carbon$-12$ isotope as the standard reference.
2. One atomic mass unit is equal to one-twelfth $(1/{12}^{\mathrm{th}})$ the mass of one atom of carbon$-12$.

Importance to measure atomic mass:

1. To find the average mass of elements and molecules.
2. To solve problems based on stoichiometry.