Question

What is the percentage composition of the elements in ammonia?

$(N=14,H=1)$

• A. $N=82.35$%, $H=17.65$%
  
• B. $N=83.35$%, $H=16.65$%
• C. $N=80.35$%, $H=19.65$%
• D. $N=81.35$%, $H=18.65$%

Answer 1

The correct option is A $N=82.35$%, $H=17.65$%

The atomic masses of $N$ and $H$ are 14 g/mol and 1 g/mol respectively.

The molecular weight of $N{H}_3$ is $14+3\left(1\right)=17$ g/mol. Thus, 17 g of $N{H}_3$ will contain 14 g of N and 3 g of H.
The percentage of N in $N{H}_3$ $=\frac{14}{17}\times 100=82.35\%$

The percentage of H in $N{H}_3$ $=100-82.35=17.65\%$