Question

A compound was found to contain nitrogen and oxygen in the ratio nitrogen 28 g and oxygen 80 g. The formula of the compound is:

• A. $NO$
• B. $N_2{O}_3$
• C. $N_2{O}_5$
• D. $N_2{O}_4$

Answer 1

Answer: (C)

$N_2{O}_5$

The atomic masses of nitrogen and oxygen are 14 and 16 g/mol respectively.

The number of moles of nitrogen $=\frac{\text{28 g}}{\text{14 g/mol}}=\text{2 mol}$

The number of moles of oxygen $=\frac{\text{80 g}}{\text{16 g/mol}}=\text{5 mol}$

The mole ratio nitrogen : oxygen $=2:5$

The formula of the compound is $N_2{O}_5$.