Question

Most fertilizers consist of nitrogen-containing compounds. Examples include NH3, CO(NH2)2, NH4NO3, and (NH4)2SO4. The nitrogen content in these compounds is needed for protein synthesis in plants.

A. Calculate the mass percent composition of nitrogen in NH3.

B. Calculate the mass percent composition of nitrogen in CO(NH2)2.

C. Calculate the mass percent composition of nitrogen in NH4NO3.

D. Calculate the mass percent composition of nitrogen in (NH4)2SO4.

E. Which fertilizer has the highest nitrogen content?

a. NH3

b. CO(NH2)2

c. NH4NO3

d. (NH4)2SO4

Answer 1

Mass percent of nitrogen in a nitrogen-containing compound can be calculated as follows:

Where n is the number of N atoms in the compound.

atomic mass of N = 14.00 g/mol

A.

There is only one N in NH3. Hence, n=1.

Molar mass of NH3 = 17.031 g/mol

Hence, we can calculate the mass percent composition of nitrogen as follows

B.

There are two N atoms in the formula. Hence, n=2.

Molar mass of = 60.06 g/mol

Hence, we can calculate the mass percent composition of nitrogen as follows

C.

There are two N atoms in the formula. Hence, n=2.

Molar mass of = 80.043 g/mol

Hence, we can calculate the mass percent composition of nitrogen as follows

D.

There are two N atoms in the formula. Hence, n=2.

Molar mass of = 132.14 g/mol

Hence, we can calculate the mass percent composition of nitrogen as follows

E.

Hence, the fertilizer with highest Nitrogen content by mass is a). with 82.2 % of the total mass being nitrogen.