A compound of nitrogen and oxygen is found to contain 30.45% nitrogen and 69.55% oxygen. Determine the empirical formula.

NO2

Explanation:

To calculate the empirical formula, what we need do first is to divide the appropriate percentage compositions with the atomic masses. The atomic mass of nitrogen is 14g/mol. The atomic mass of oxygen is 16g/mol

We proceed like this:

N = 30.45/14 = 2.175

O = 69.55/16 = 4.347

We then divide both by the smallest of the numbers.

N = 2.175/2.175 = 1

O = 4.347/2.175 = 2

The empirical formula is thus NO2