CBSE Class 6 Answered

The concept of mole was introduced to know the number of atoms or molecules involved while performing a reaction.

The quantity of a substance is expressed in mole.

     Mole

A mole is defined as the amount of substance which contains as many specified elementary particles as the number of atoms in 12 g of the carbon-12 isotope.

One mole is also defined as the amount of substance which contains Avogadro number (6.023 × 10²³) of particles.

     Avogadro’s number

The number of atoms or molecules or ions present in one mole of a substance is called Avogadro’s number. Its value is 6.023 × 10²³.

     Important formulae to find the number of moles

Number of moles = Mass

                               Atomic mass

Number of moles = Mass

                               Molecular mass

Number of moles = Number of atoms

                                  6.023 × 10²³

Number of moles = Number of molecules

                                    6.023 × 10²³