Question

How many moles are present in 28g of nitrogen atoms?

Answer 1

1 mole of Nitrogen is 14 grams 

No. of moles present in 28g will be $\frac{28}{14}=2 moles$

since 1 mole of nitrogen contains $6.022* 10^{23}$ atoms

∴ 2 moles of Nitrogen have $6.022* 10^{23} *2 = 12.044* 10^{23}$ atoms

Answer 2

2 moles of ${ N }_{ 2 }$ are present in 28 g/mol of nitrogen.

Mole can be defined as the "number" of carbon atoms present in exactly "12 grams" of pure Carbon.

One mole of any molecule consists $6.022\quad \times \quad { 10 }^{ 23 } molecules.$

Hence,

Molecular mass of nitrogen = 28 g = 1 mole

28 grams of nitrogen contains $6.022\quad \times { 10 }^{ 23 } molecules\quad of\quad { N }_{ 2 }$

Each nitrogen molecule $({ N }_{ 2 })$ has two nitrogen atom.

$Total\quad molecules\quad in\quad { N }_{ 2 }\quad =\quad 6.022\quad \times { 10 }^{ 23 }\quad \times \quad 2\quad =\quad 12.044\quad \times { 10 }^{ 23 }\quad molecules.$