Chapter 6, Problem 6STP

Interpretation Introduction

Interpretation:

The percentage of nitrogen in the compound ${\text{N}}_{\text{2}}{\text{O}}_{\text{3}}$ needs to be determined.

Concept introduction:

To calculate the percentage composition of an element in a compound, the following formula is to be used.

$\%\text{composition}\text{of}\text{element=}\frac{\text{Mass}\text{of}\text{element}\text{in}\text{the}\text{compound}}{\text{Molar}\text{mass}\text{of}\text{the}\text{compound}}\times 100\%$

Answer to Problem 6STP

The correct option is D, 36.8%.

Explanation of Solution

First calculate the molecular mass of the compound.

$\begin{array}{c}\text{The molecular mass of the compound}{\text{N}}_{\text{2}}{\text{O}}_{\text{3}}=2\times 14\text{g}{\text{mol}}^{-1}+3\times 16\text{g}{\text{mol}}^{-1}\\ =28\text{g}{\text{mol}}^{-1}+48\text{g}{\text{mol}}^{-1}\\ =76\text{g}{\text{mol}}^{-1}\end{array}$

Then calculate percentage composition.

$\begin{array}{c}\%\text{composition}\text{of}\text{Nitrogen=}\frac{\text{Mass}\text{of}\text{Nitrogen}\text{in}{\text{N}}_{\text{2}}{\text{O}}_{\text{3}}}{\text{Molar}\text{mass}\text{of}{\text{N}}_{\text{2}}{\text{O}}_{\text{3}}}\times 100\\ \text{=}\frac{28\text{g}{\text{mol}}^{-1}}{76\text{g}{\text{mol}}^{-1}}\times 100\\ =36.8\%\end{array}$

Conclusion

Thus, the percentage composition of the nitrogen in ${\text{N}}_{\text{2}}{\text{O}}_{\text{3}}$ is 36.8.