Question

Most fertilizers consist of nitrogen-containing compounds such as NH3,CO(NH2)2,NH4NO3, and (NH4)2SO4. Plants use the nitrogen content in these compounds for protein synthesis. Calculate the mass percent composition of nitrogen in each of the fertilizers listed. Which fertilizer has the highest nitrogen content?

Answer 1

Answer: 1. $NH_3=82.4\%$

2.  $CO(NH_2)_2=46.7\%$

3. . $NH_4NO_3=35\%$

4. $(NH_4)_2SO_4=21.2\%$

$NH_3$ has highest nitrogen content.

Explanation:

To calculate the mass percent of element in a given compound, we use the formula:

$\text{Mass percent of nitrogen}=\frac{\text{Mass of nitrogen}}{\text{Molar mass of nitrogen compound}}\times 100$

1. $NH_3$

$\text{Mass percent of nitrogen}=\frac{\text{Mass of nitrogen}}{\text{Mass of} NH_3}=\frac{14}{17}\times 100=82.4\%$

2. $CO(NH_2)_2$

$\text{Mass percent of nitrogen}=\frac{\text{Mass of nitrogen}}{\text{Mass of} CO(NH_2)_2}=\frac{14\times 2}{12\times 1+16\times 1+2\times 14+4\times 1}\times 100=\frac{28}{60}\times 100=46.7\%$

3. $NH_4NO_3$

$\text{Mass percent of nitrogen}=\frac{\text{Mass of nitrogen}}{\text{Mass of} NH_4NO_3}=\frac{14\times 2}{14\times 2+16\times 3+4\times 1}\times 100=\frac{28}{80}\times 100=35\%$

4. $(NH_4)_2SO_4$

$\text{Mass percent of nitrogen}=\frac{\text{Mass of nitrogen}}{\text{Mass of}(NH_4)_2SO_4}=\frac{14\times 2}{14\times 2+16\times 4+32\times 1+8\times 1}\times 100=\frac{28}{132}\times 100=21.2\%$

Thus $NH_3$ has highest nitrogen content  of 82.4%.