When solid mercury (ii) nitrate is heated, it decomposes to form solid mercury (ii) oxide, gaseous nitrogen dioxide, and oxygen?

I believe the statement given above is true. When solid mercury (ii) nitrate is being heated, a decomposition reaction happens. The solid would decompose into 3 different substances - solid mercury (ii) oxide, gaseous nitrogen dioxide, and oxygen. The balanced chemical reaction would be written as:

2Hg (NO3) 2 = 2HgO + 4NO2 + O2

Decomposition reaction is a type of reaction where it involves a single compound breaking down into two or more products. These reactions often requires an energy source thus it is an endothermic reaction. This is evident for this reaction since we supplied heat to the reactant for the reaction to proceed.