In which type of reaction do substances combine to form one product?

A synthesis reaction is characterized by the combination of two or more substances to produce a single product. This type of reaction is fundamental in chemistry and is exemplified by the equation A + B → AB, where A and B represent reactants that come together to form the compound AB.

Synthesis reactions are vital in various processes, including the formation of water from hydrogen and oxygen gases. In such reactions, energy is usually released or absorbed, depending on the nature of the compounds involved, but the key takeaway is the formation of one distinct product from the reactants.

In contrast, decomposition reactions involve breaking down a compound into simpler substances; single displacement reactions occur when one element replaces another in a compound; and double displacement reactions involve the exchange of ions between two compounds to form two new compounds. These concepts highlight the unique nature of synthesis reactions in producing a single, new product.