Mole:
Mole can be defined as amount of the substance that contains as many particles or entities or atoms exactly in 12 gm of the C-12 isotope.
1 atom of C-12 weighs ———1.99×10-23gm
How may atoms will be in——12 gm
Therefore 12×1/1.99×10-23=6.023×1023atoms.
These number of atoms in c-12 isotope can be mentioned as Avagadro number of atoms.
1 mole of any substance consists of avagadro number of atoms/molecules/ions i.e;6.023×1023atoms/molecules/ions.
Avagadro number is indicated with capital letter ‘N’
N value is 6.023×1023atoms/molecules/ions.
For example:
1 mole of H2O molecule consists of N number of water molecules.
1 mole of H2O molecule consists of 2N number of hydrogen atoms.
1 mole of H2O molecule consists of 1N number of oxygen atoms.
Molar mass:
Molar mass can be defined as mass of 1 mole of substance in grams.
For example: 1 mole of H2O weighs 18gm.
1 mole of CO2 weighs 44gm.
Percentage composition:
Generally the molecule is made of atoms.if we consider the molecule is 100% then we should find the percentage composition of individual atoms or elements in the given molecule or compound.
For example:
Lets find the percentage composition of hydrogen and oxygen in water molecule.
Total is 99.9% which is nearly equal to 100%.
