What compound consists of 0.248 g magnesium, 0.655 g sulfur, and 1.31 g oxygen

Magnesium Peroxydisulphate with formula of MgS₂O₈.

Explanation:

The question clearly stands on the concept of molarity and atomic weights.

The atomic weight of magnesium = 24.

The atomic weight of sulphur = 32.

The atomic weight of oxygen = 16.

The amount of magnesium present = 0.248 g

The amount of sulphur present = 0.665 g.

The amount of oxygen present = 1.31g.

So, moles of magnesium present = 0.01 moles.

Moles of sulphur present = 0.02 moles.

Moles of oxygen present = 0.08 moles.

So, mole ratio of the compound as magnesium : sulphur : oxygen = 1:2:8.

So the compound is Magnesium Peroxydisulphate with formula of MgS₂O₈.