Final answer:
In a decomposition reaction, a single compound breaks down to give two or more simpler products, resulting in more reactant molecules than product molecules.
Step-by-step explanation:
The type of reaction where there are more reactant molecules than product molecules is a decomposition reaction. In a decomposition reaction, a single compound breaks down into two or more simpler products. These products can be elements, compounds, or a mixture of both. The general form of a decomposition reaction can be represented as:
AB → A + B
Contrastingly, in a combination reaction, multiple reactants combine to form a single product, in a single displacement reaction, one element replaces another element in a compound, and in a double displacement reaction, the cations and anions of two different compounds switch partners, often producing a precipitate, gas, or a molecular compound such as water.