Chapter 3, Problem 11QP

All the substances listed here are fertilizers that contribute nitrogen to the soil. Which of these is the richest source of nitrogen on a mass percentage basis?

(a)

Urea $\left[{\left({\text{NH}}_{\text{2}}\right)}_{\text{2}}\text{CO}\right]$

(b)

Ammonium nitrate $\left({\text{NH}}_{\text{4}}{\text{NO}}_{\text{3}}\right)$

(c)

Guanidine $\left[\text{HNC}{\left({\text{NH}}_{\text{2}}\right)}_{\text{2}}\right]$

(d)

Ammonia $\left({\text{NH}}_{\text{3}}\right)$