Question

The percentage by weight of nitrogen in ammonium nitrate is _____

Answer 1

Definition of Percentage by weight

• It is defined as the mass percent composition of an element in a compound
• It can be abbreviated as w/W %

$\mathrm{Percentage}\mathrm{by}\mathrm{weight}=\frac{\mathrm{weight}\mathrm{of}\mathrm{the}\mathrm{element}}{\mathrm{weight}\mathrm{of}\mathrm{compound}}\mathrm{x}100\%$

Percentage by weight of nitrogen in ammonium nitrate

• Let us calculate the mass of ammonium nitrate ${\mathrm{NH}}_4{\mathrm{NO}}_3=2\mathrm{x}\mathrm{mass}\mathrm{of}\mathrm{N}+4\mathrm{x}\mathrm{mass}\mathrm{of}\mathrm{H}+3\mathrm{x}\mathrm{mass}\mathrm{of}\mathrm{O}$

$=2\mathrm{x}14+4\mathrm{x}1+3\mathrm{x}16$

$=80\mathrm{g}$

• The total mass of nitrogen$=2\mathrm{x}14=28\mathrm{g}$
• Therefore the percentage by weight of nitrogen in ammonia is:

$$\begin{gathered} \mathrm{Percentage}\mathrm{by}\mathrm{weight}=\frac{\mathrm{weight}\mathrm{of}\mathrm{Nitrogen}}{\mathrm{weight}\mathrm{of}\mathrm{ammonium}\mathrm{nitrate}}\mathrm{x}100\% \\ =\frac{28}{80}\mathrm{x}100\%=35\% \end{gathered}$$

Conclusion: The percentage by weight of nitrogen in ammonium nitrate is 35%