Question

The following compounds containing only nitrogen and oxygen are all gases in the atmosphere with varying activities. Which one of these four has the highest mass percent of N? Defend your choice by calculating the mass percent of N in it.
NO NO2 N2O N2O4

Answer 1

Answer: $N_2O$ has the highest mass percent of nitrogen.

Explanation:

To calculate the percentage composition of a nitrogen in a compound, we use the equation:

$\%\text{ composition of nitrogen}=\frac{\text{Mass of nitrogen}}{\text{Mass of compound}}\times 100$      .......(1)

Molar mass of nitrogen = 14 g/mol

• For NO:

Mass of NO = 30.01 g/mol

Mass of nitrogen = $[1\times 14]=14g/mol$

Putting values in equation 1, we get:

$\%\text{ composition of nitrogen}=\frac{14g}[30.01}\times 100\\\\\%\text{ composition of nitrogen}=46.65\%$

The mass percent of nitrogen in given compound is 46.65 %

• For $NO_2$ :

Mass of $NO_2$ = 46.01 g/mol

Mass of nitrogen = $[1\times 14]=14g/mol$

Putting values in equation 1, we get:

$\%\text{ composition of nitrogen}=\frac{14g}[46.01}\times 100\\\\\%\text{ composition of nitrogen}=30.43\%$

The mass percent of nitrogen in given compound is 30.43 %

• For $N_2O$ :

Mass of $N_2O$ = 44.01 g/mol

Mass of nitrogen = $[2\times 14]=28g/mol$

Putting values in equation 1, we get:

$\%\text{ composition of nitrogen}=\frac{28g}[44.01}\times 100\\\\\%\text{ composition of nitrogen}=63.62\%$

The mass percent of nitrogen in given compound is 63.62 %

• For $N_2O_4$ :

Mass of $N_2O_4$ = 92.01 g/mol

Mass of nitrogen = $[2\times 14]=28g/mol$

Putting values in equation 1, we get:

$\%\text{ composition of nitrogen}=\frac{28g}[92.01}\times 100\\\\\%\text{ composition of nitrogen}=30.43\%$

The mass percent of nitrogen in given compound is 30.43 %

Hence, $N_2O$ has the highest mass percent of nitrogen.