In Chemistry Avogadro number is defined as the number of particles ( atom or molecule ) found in one molecule of a substance. It is a number of atom in a 12 g sample of carbon- 12. It has dimensions of reciprocal mol and its value is equal to 6.0221367 × 1023 .per mole, which is 6.023
× 1023. Avogadro number is also known as Avogadro constant.