Question

Describe mole concept

Answer 1

one mole is the amount of a substance that contains as many particles or entities as there are atom in exactly 12 g of the carbon 12

Answer 2

1.  One mole  of a substance is equal to the amount with Avogadro number of particles (atoms or molecules) in it.  Avogadro number is N = 6.022 * 10^23.     One mole of a substance weighs as much as the moelcular weight in grams.

2.  One mole of carbon (atomic mass = 12 amu) isotope contains N number of atoms.  Its mass is 12  grams. One mole of Oxygen (O2) with a molecular mass = 32 amu, has a mass of 32 grams.  One mole of H2O thus weighs 18 grams.

3.  Further one mole of a gas occupies 22.4 litres volume at STP.

4.  P V = n R T ,    the ideal gas equation involves the number  n of moles.
        Pressure, volume, Temperature of an ideal gas are linked through number of moles.

5.  In a chemical reaction, we balance mass in terms of multiples of moles of substances.
            Na OH + H Cl ==> H2 O  + Na Cl
       One mole each of sodium hydroxide and Hydrochloric acid react with one mole each of water and  Salt.