I think most of the students know about mole and Avogadro’s number but this question arises to many students **“Relation between Mole and Avogadro’s number”**. In this tutorial i shall try to clarify this point.

First of all we should pass through the definitions of following terms:

## Mole:

Mole is the amount of substance which contain

6.02 * 10 ^23atoms, molecules or formula units.

## Avogadro’s Number:

It is the specific number 6.02 * 10^23, which identify the number of atoms, molecules and formula units of any compound.

## Relation between Mole and Avogadro’s Number:

For example one atom of carbon have atomic mass of 12g, it means 12 grams of carbon will contain 6.02 * 10^23 atoms in it.

Let we take another example: If we calculate molecular mass of water (H2O), answer is 18 grams (as 2+16=18), this means 18 grams of water will contain 6.02 * 10^23 molecules.

If we consider NaCl, we can calculate total number of formula units: as formula mass of NaCl is 58.5 grams [Na(23)+Cl(35.5)] then there will be 6.02 * 10^23 formula units are present.

**In Short:**

- Any Element has specific atomic mass: which is equal to one mole: and one mole contain 6.02 * 10^23 atoms.

Example: Atomic mass of Oxygen is 16: which is equal to one mole: and one mole contain 6.02 * 10^23 atoms.

- Any molecule has specific molecular mass: which is equal to one mole: and one mole contain 6.02 * 10^23 molecules.

Example: Molecular mass of NH3 is 17: which is equal to one mole: and one mole of NH3 contain 6.02 * 10^23 molecules.

- Any Ionic compound has specific formula mass: which is eqaul to one mole: and one mole of Ionic compound e.g. NaCl contain 6.02 * 10^23 formula units.