The mass fraction of sulfur in its oxide is 1.5 times less than the mass fraction of oxygen. Determine the oxide formula.

Let the mass fraction of oxygen be 1.5 x, the mass fraction of sulfur – x.

Let’s make an equation.

1.5 x + x = 1,

2.5 x = 1,

X = 1: 2.5,

X = 0.4

0.4 x 100 = 40% (S).

100% – 40% = 60% (O).

Let’s find the mass of the atoms.

100 g – 100%,

m g (S) – 40%,

m g (S) = (100 g × 40%): 100% = 40 g.

100 g – 100%,

m g (O) – 60%,

m g (O) = (100 g × 60%): 100% = 60 g.

M (S) = 32 g / mol,

M (O) = 16 g / mol.

We find the number of substances of atoms.

n (S) = 40 g: 32 g / mol = 1.25 mol.

n (O) = 60 g: 16 g / mol = 3.75 mol.

Let’s find the ratio of the amounts of substances of atoms.

S: O = 1.25 mol: 3.75 mol = 1: 3.

Formula SO3.