Two different compounds are formed by the elements nitrogen and oxygen. The first compound, compound P1, contains 64.17% by mass nitrogen and 35.73% by mass oxygen. The second compound, compound P2, contains 47.23% by mass nitrogen and 52.79% by mass oxygen. What is the ratio of nitrogen to a fixed mass of oxygen for the two compounds?

To solve the problem, we must know the kind of compounds we are dealing with.

For the first compound, P1 and second compound P2:

N O N O

Mass percent 64.17 35.73 47.23 52.79

Atomic mass 14 16 14 16

Number of

moles 64.17/14 35.73/16 47.23/14 52.79/16

4.58 2.23 3.37 3.30

Simplest

ratio 4.58/2.23 2.23/2.23 3.37/3.30 3.3/3.3

2 1 1 1

P1 compound is N₂O

P2 compound is NO

These are the compounds,

In N₂O = 28:16

NO = 14:16

This is the ratio of nitrogen to a fixed mass of oxygen for the two compounds.