Question

Magnesium and oxygen combine in the ratio of 3:2 by mass to form magnesium oxide how much oxygen is required toreact completely with 12g of magnesium

Answer 1

The ratio between Mg : O is equal 3:2

Due to the ratio of atomic masses 24:16

So

if we have 12 g of Mg its mean 4 × 3

, we well have 4×2 the oxygen

So the mass of oxygen = 8 gms