Determine the mass fraction of oxygen in NaNO3.

Sodium nitrate has the following chemical formula NaNO3;

Its molecule consists of 1 sodium atom, 1 nitrogen atom, 3 oxygen atoms.

In order to calculate the mass fraction of the elements included in the molecule, it is necessary to find the ratio of the molar weights of the atoms of these elements to the molar weight of the molecule.

M 3O = 16 x 3 = 48 grams / mol;

M NaNO3 = 23 + 14 + 16 x3 = 85 grams / mol;

The mass fraction of oxygen will be:

K O = 48/85 = 0.565 = 56.5%;