Question

The molecular formula of ammonia is ${NH}_3$. Therefore, the number of hydrogen atoms in $34$ g of ammonia will be :

• A. $3\times 6.023\times {10}^{23}$
• B. $6.023\times {10}^{23}$
• C. $34\times 6.023\times {10}^{23}$
• D. $6\times 6.023\times {10}^{23}$

Answer 1

Answer: (D)

$6\times 6.023\times {10}^{23}$

The atomic weight of ${NH}_3=(14+3$\times $1)=17g.$

Now,

17g = 1 mole of ${NH}_3$

so, 34 g = ?

= $\frac{34}{17}$

= 2 mole.

now, 1 mole of ${NH}_3$ has 3 atoms of hydrogen

so, 2 mole will have 3 $\times$ 2 = 6 H atoms.

1 atom = ${6.023\times 10}^{23}$

so, 6 atoms = $6\times {6.023\times 10}^{23}$