what is mole in chemistry

In chemistry, a mole is defined as the amount of a chemical substance that contains as many elementary entities, such as atoms, molecules, ions, electrons, or photons, as there are atoms in 12 grams of carbon-12. This number is expressed by the Avogadro constant, which is approximately (6.022 \times 10^{23}) per mole. The mole is a fundamental concept in chemistry and is used as a unit of measurement for the amount of a substance. It is widely used to express amounts of reactants and products in chemical reactions and to convert between the mass and number of particles of a substance