No, the heating of calcium carbonate is not a synthesis reaction. It's a decomposition reaction. Here's why:

* Synthesis Reaction: A synthesis reaction involves combining two or more reactants to form a single, more complex product. For example:

* A + B → AB

* Decomposition Reaction: A decomposition reaction involves breaking down a single reactant into two or more simpler products. For example:

* AB → A + B

The reaction of heating calcium carbonate:

Calcium carbonate (CaCO₃) when heated decomposes into calcium oxide (CaO) and carbon dioxide (CO₂):

CaCO₃ (s) → CaO (s) + CO₂ (g)

In this case, a single reactant (calcium carbonate) is breaking down into two products (calcium oxide and carbon dioxide). This is a classic example of a decomposition reaction.