Question

All the substances listed below are fertilizers that contribute nitrogen to the soil.

Answer 1

Answer:

Ammonia is the richest source of nitrogen on a mass percentage basis because it has 82.35% of nitrogen by mass.

Explanation:

Percentage of element in compound :

$=\frac{\text{number of atoms}\times text{Atomic mass}}{\text{molar mas of compound}}\times 100$

(a) Urea, $(NH_2)_2CO$

Molar mass of urea = 60 g/mol

Atomic mass of nitrogen = 14 g/mol

Number of nitrogen atoms = 2

$N\%=\frac{2\times 14 g/mol}{60 g/mol}\times 100=46.67\%$

(b) Ammonium nitrate, $NH_4NO_3$

Molar mass of ammonium nitrate = 80 g/mol

Atomic mass of nitrogen = 14 g/mol

Number of nitrogen atoms = 2

$N\%=\frac{2\times 14 g/mol}{80 g/mol}\times 100=35.00\%$

(c) Nitric oxide, NO

Molar mass of nitric oxide  = 30 g/mol

Atomic mass of nitrogen = 14 g/mol

Number of nitrogen atoms = 1

$N\%=\frac{1\times 14 g/mol}{30 g/mol}\times 100=46.67\%$

(d) Ammonia, $NH_3$

Molar mass of ammona = 17 g/mol

Atomic mass of nitrogen = 14 g/mol

Number of nitrogen atoms = 1

$N\%=\frac{1\times 14 g/mol}{17 g/mol}\times 100=82.35\%$​

Ammonia is the richest source of nitrogen on a mass percentage basis because it has 82.35% of nitrogen by mass.