Calcium carbonate decomposes on heating to form calcium oxide and carbon dioxide

Calcium carbonate decomposes on heating to form calcium oxide and carbon dioxide. When 10 g of calcium carbonate is decomposed completely then 5.6 g of calcium oxide is formed? Calculate the mass of carbon dioxide formed. Which law of chemical combination will you use in solving this problem? State the law.

The reaction occurs as follows:
$CaC{{O}{3}}$ --------------------> CaO + C02
According to the law of conservation of mass,
Total mass of reactant(s) = Total mass of products (s)
=> 10 g = 5.6 g + Mass of $C{{O}
{2}}$
=> Mass of C02 = 10 - 5.6 = 4.4 g
This problem is solved using law of conservation of mass according to which mass can neither be created nor be destroyed during a chemical reaction.