It is important to ensure that plants have the correct nutrient to ensure sufficient food production. There are three main elements required for plant growth; nitrogen, phosphorus and potassium.

Part of

As with metal ores, it is useful to be able to calculate exactly what proportion the essential nutrients accounts for in a fertiliser.

- Question
Ammonium nitrate (NH

_{4}NO_{3}) is commonly used as a fertiliser. Given the relative atomic mass of hydrogen is 1, nitrogen is 14 and oxygen is 16, calculate the percentage of ammonium nitrate that is nitrogen.Begin by calculating the formula mass.

The percentage of ammonium nitrate that is nitrogen is given by the formula:

\[\% \,of\,N\,in\,N{H_4}N{O_3} = \frac{{mass\,of\,N\,in\,N{H_4}N{O_3}\,}}{{formula\,mass\,of\,N{H_4}N{O_3}}} \times 100\]

\[\begin{array}{l} = \frac{{28}}{{80}} \times 100\\ = 35\% \end{array}\]

Ammonium nitrate is 35 per cent nitrogen.