Question

The number of molecules in 34.0g of $N{H}_3$ is ____.

• A. $36.12\times {10}^{23}$
• B. $18.06\times {10}^{23}$
• C. $12.04\times {10}^{23}$
• D. $6.02\times {10}^{23}$

Answer 1

The correct option is C $12.04\times {10}^{23}$

The molecular formula of ammonia is $N{H}_3$.
The molar mass of ammonia is 17.
17 g or 1 mole of $N{H}_3$ = $6.023\times {10}^{23}$ molecules.
So, 34 g of $N{H}_3$ = $\frac{6.022\times {10}^{23}\times 34}{17}$
= $12.044\times {10}^{23}$ molecules.