Question

Calllculate the no of atoms present in 20 gm of na2 co3 the given atomic mass of na = 23 c=12 0= 16v

Answer 1

Solution :

Concept : To calculate number of atoms we first need to find the moles of the given compound. Then multiplying the moles with Avogadro number we get the number of molecules. Multiplying the Number of atoms in the Compound, we get the Number of atoms.

Illustration : Number of Moles = Given Mass / Molecular Mass

Molecular Mass = 23 ( 2 ) + 12 + 16 ( 3 )

Molecular Mass = 46 + 12 + 48 = 106 g

Given Mass = 20 g

Hence Number of Moles = 20 g / 106 g  = 0.18 Moles

So One mole = Avogadro Number of Molecules. Then 0.18 moles will have

=> 6.022 × 10²³ × 0.18 / 1  

=> 1.08396 × 10²³ Molecules.

Number of Atoms in this compound :-

Na - 2, C - 1, 0 - 3

Therefore Total number = 2 + 1 + 3 = 6 Atoms

Therefore Number of Atoms = 6 × 1.08396 × 10²³ Atoms

=> 6.50376 × 10²³ Atoms.

Hope my answer helped !