Sulfur dioxide is an atmospheric pollutant. Sulfur dioxide pollution is reduced by reacting calcium oxide with sulfur dioxide to
produce calcium sulfite.
CaO + SO2 → CaSO3
7.00 g of calcium oxide reacts with an excess of sulfur dioxide.
Relative atomic masses (Ar): O = 16 S = 32 Ca = 40 Calculate the mass of calcium sulfite produced

The mass of calcium sulfite produced : 15 g

A reaction coefficient is a number in the chemical formula of a substance involved in the reaction equation. The reaction coefficient is useful for equalizing reagents and products.

Reaction

CaO + SO₂ → CaSO₃

mol CaO (MW=56 g/mol)

Because sulfur dioxide is an excess, so mol CaSO₃ based on mol CaO

From the equation, mol ratio of mol CaSO₃ : mol CaO=1 : 1, so mol CaSO₃ :

mass CaSO₃ (MW=120 g/mol) :

the product of the pressure and volume is also constant