Find the difference in number of sigma bonds in the reactant and products when ammonium carbonate is heated.

When ammonium carbonate is heated, it gives gaseous ammonia and gaseous carbon dioxide along with water molecule according to the following chemical reaction,

${\left({\mathrm{NH}}_4\right)}_2{\mathrm{CO}}_3\stackrel{\Delta }{⟶}2{\mathrm{NH}}_3+{\mathrm{CO}}_2+{\mathrm{H}}_2\mathrm{O}$

Now, considering the fact that each single bond is made up of one $\sigma$ bond and each double bond consists of one $\sigma$ bond and one $\mathrm{\pi }$-bond,.

Structure of ammonium carbonate is:

Number of sigma bonds on the reactant side $=11$

Number of sigma bonds on the product side $=10$ (because there are six sigma bonds in 2NH₃, two sigma bonds in CO₂ and two sigma bonds in H₂O)

Hence, the difference in the number of $\sigma$ bonds in the reactant and product when ammonium carbonate is heated is $11-10=1$