0Mole is the foundation of Chemistry. It is the fundamental thing, yet many students get difficulty in understanding this concept & there are various reasons for different students.
In this lesson, I am going to talk about mole concept in very basic detail.
The mole is the unit of measurement for the amount of substance in the International System of Units (SI). Just like kg for mass, litre for volume. we can relate mole to a dozen in an interesting way as we define dozen as an amount which contains 12 number of units of anything in the same way 1 mole is the amount of any substance which contains 6.022 × 10^23 entities
here entities can be anything like atoms, molecules, ions, electrons, protons or neutrons
e.g. 1 mole = 6.022×10^23 atoms
1 dozen = 12 atoms or bananas
Standard definition - it is the amount of substance which contains the same number of entities as there are in 12 gm of the C-12 atom.
further, it was found that number of entities are 6.022×10^23
Carbon-12 is the most abundant stable isotope of carbon, and it is used for measuring atomic masses of all nuclides.
Relation of moles with mass, Volume & Number of entities
as we know,
1 mole contains 6.022×10^23 entities
number of moles = Number of entities⁄6.022×10^23
in the same way as 12 gm of carbon contain 1 mole
then we can write
no of moles = mass in grams/molecular mass(atomic mass)
and by Avogadro's law which says the equal volume of gases contain an equal number of molecules irrespective of nature of gases
we can write
number of moles=Volume at STP(litre)/22.4
