# How many atoms are present in 1.25 g of molecular hydrogen?

## Question:

How many atoms are present in 1.25 g of molecular hydrogen?

## Mole Concept

Mole is equal to the Avogadro's number and represented by {eq}N_{A} {/eq}. A mole is equal to as many particles as there in the one-twelfth the mass of a C-12 atom. It is the fundamental unit of the amount of substance.

Number of atoms is given by the formula,

{eq}Number\,of\,atoms\, = \frac{Mass}{Molar \, mass} \times 6.022 \times 10^{23} \\ Number\,of\,atoms\, = \frac{1.25}{2} \times 6.022 \times 10^{23} \times 2 \\ Number\,of\,atoms\, = 1.50 \times 10^{24} {/eq}