Question

How do you write the equation to represent “Calcium sulfite decomposes to form calcium oxide and sulfur dioxide”?

Answer 1

The given chemical compounds undergo decomposition reaction where a single reactant calcium sulfite breaks down under the influence of heat into two main product calcium oxide and sulfur dioxide.

Complete step by step answer:
It is given that calcium sulfite decomposes to form calcium oxide and sulfur dioxide.
The reaction taking place in the given statement is a decomposition reaction. The decomposition reaction is defined as the reaction where a single reactant compound breaks down into two or more than two product compounds.
In the chemical compound calcium sulfite the suffix –ite is used for polyatomic anion containing oxygen atoms. The compound calcium sulfite contains three oxygen atoms. In calcium sulfite, the calcium ion forms a cation with +2 oxidation state and sulfite ion forms an anion with -2 oxidation state. So, the chemical formula or molecular formula of calcium sulfite is $CaS{O_3}$. In calcium oxide, the calcium forms an cation with +2 oxidation state and oxygen forms an oxide anion with -2 oxidation state. Thus, the molecular formula of calcium oxide is CaO. In sulphur dioxide, one sulphur atom is present and the prefix di- denotes that two oxygen atoms are present. The molecular formula of sulphur dioxide is $S{O_2}$.
The name reaction is given as shown below.
$Calcium\;sulfite \to calcium\;oxide + sulfur\;dioxide$
The chemical equation is given as shown below.
$CaS{O_3}(s) \to CaO(s) + S{O_2}(g)$

Note:
The equation is already balanced as the number of atoms on both sides of the reaction is equal. Don’t get confused by the chemical formula of calcium sulfite as it contains three oxygen atoms and sulfate ion contains four oxygen atoms.