Question

Calculate the percentage of nitrogen in ammonium nitrate. $\left(\mathrm{H}=1,\mathrm{N}=14,\mathrm{O}=16\right)$

Answer 1

Step 1: Given information

The given compound is ammonium nitrate $\left({\mathrm{NH}}_4{\mathrm{NO}}_3\right)$.

Step 2: Calculate the molecular mass of ammonium nitrate

• Mass of Nitrogen $\left(\mathrm{N}\right)$ element$=14\mathrm{g}$
• Mass of Hydrogen $\left(\mathrm{H}\right)$ element$=1\mathrm{g}$
• Mass of Oxygen $\left(\mathrm{S}\right)$ element$=32\mathrm{g}$
• To determine molecular mass, multiply the number of atoms by the mass of that element and sum the masses of all the elements in the compound.
• The molecular mass of ${\mathrm{NH}}_4{\mathrm{NO}}_3$ is as follows:

$$\begin{gathered} \mathrm{Molecular}\mathrm{mass}\mathrm{of}{\mathrm{NH}}_4{\mathrm{NO}}_3=\left(14\mathrm{g}\times 2\right)+\left(1\mathrm{g}\times 4\right)+\left(16\mathrm{g}\times 3\right) \\ =80\mathrm{g} \end{gathered}$$

Step 3: Formula used to determine the percentage composition

$\mathrm{Percentage}\mathrm{composition}=\frac{\mathrm{Mass}\mathrm{of}\mathrm{the}\mathrm{element}\mathrm{in}\mathrm{one}\mathrm{molecule}\mathrm{of}\mathrm{a}\mathrm{compound}}{\mathrm{Gram}\mathrm{molecular}\mathrm{mass}\mathrm{of}\mathrm{the}\mathrm{compound}}\times 100$

Step 4: Calculate the percentage of Nitrogen in ${\mathrm{NH}}_4{\mathrm{NO}}_3$

• $80\mathrm{g}$ of ${\mathrm{NH}}_4{\mathrm{NO}}_3$ contains $14\mathrm{g}\times 2=28\mathrm{g}$ of Nitrogen.
• The calculation is as follows:
• $$\begin{gathered} \mathrm{Percentage}\mathrm{of}\mathrm{Nitrogen}=\frac{28\mathrm{g}}{80\mathrm{g}}\times 100 \\ =35\% \end{gathered}$$

Thus, the percentage of nitrogen in ammonium nitrate is $35\%$.