What is the scientific definition of Mole?
One mole is defined as the amount of substance that contains the same number of atoms, molecules or particles as there are atoms in 12 grams of carbon-12.
Carbon-12 is an isotope of carbon, and 12 grams of it contains 6.022 x 1023 atoms.
1 mole of C-12
What is Avogadro’s number?
The number 6.022 x 1023is the Avogadro’s number, named after the Italian scientist Amedeo Avogadro who came up with this concept.
Amedeo Carlo Avogadro
Examples of 1 mole of a substance
One mole of gold
We know that 1 mole of gold contains 6.022 x 1023 atoms of gold or atoms equal to Avogadro’s number.
But this does not mean that the mass of 1 mole of gold is equal to 12 grams of carbon. This is because the mass of 1 atom of gold is different from the mass of 1 atom of Carbon-12.
Experimentally, it is found that the mass of 1 mole of gold is 196.97 grams.
Atoms of Gold
One mole of water
1 mole of water also has the same number of molecules as the number of atoms in 12 gram of carbon-12. This is equal to Avogadro’s number: 6.022 x 1023.
Again this does not mean that the mass of 1 mole of water is equal to 12 grams of Carbon-12. Experimentally, it is found that the mass of 1 mole of water is 18.015 grams.
Atoms of Water
The number of atoms/molecules/or any other particles in 1 mole of any substance remains the same, that is equal to Avogadro’s number 6.022 𝑥 1023, but the mass of 1 mole is different for different substances.