Question

Calculate the total number of electrons present in 1.4 g of dinitrogen gas.

Answer 1

Molecular mass of N₂ = 28 g

28 g of N₂ has No. of molecules = 6.022 x 10²³ x 1.4 g of

N₂ has No. of molecules = `(6.022 xx 10^23 xx 1.4 " g")/(28 " g")`

= 0.3011 x 10²³ molecules.

Atomic No. of Nitrogen (N) = 7

1 molecule of N₂ has electrons = 7 x 2 = 14

0.3011 x 10²³ molecules of N₂ have electrons

= 14 x 0.3011 x 10²³

= 4.215 x 10²³ electrons.

Answer 2

Molar mass of dinitrogen (N₂) = 28 g mol^–1

Thus, 1.4 g of `"N"_2 = 1.4/28 = 0.05 " mol"`

`= 0.05 xx 6.02 xx 10^(23)" number of molecules"`

`= 3.01 xx 10^23` number of molcules

Now, 1 molecule of `"N"_2` contains 14 electrons.

Therefore, 3.01 × 10²³ molecules of N₂ contains = 1.4 × 3.01 × 10²³

= 4.214 × 10²³ electrons