Combination Reaction
Definition and meaning of Combination Reaction in chemistry.
A combination reaction is a chemical reaction in which two or more reactants join together to form a single, more complex product. It follows the general pattern A + B → AB.
In more detail
The reactants may be two elements, an element and a compound, or two compounds, but the reaction always produces exactly one product. Combination reactions are also called synthesis reactions and are frequently exothermic, since forming new bonds releases energy. They are the conceptual opposite of decomposition reactions, in which a single compound breaks apart into two or more products. This reaction type is central to industrial synthesis, such as the Haber process for making ammonia.
Key facts
| General form | A + B → AB |
|---|---|
| Also known as | Synthesis reaction |
| Example equation | 2H2 + O2 → 2H2O |
| Field | General Chemistry |
Hydrogen gas reacts with oxygen gas to form water: 2H2(g) + O2(g) → 2H2O(l). Two elements combine into a single compound, releasing a large amount of heat.
Frequently asked questions
Is a combination reaction the same as a synthesis reaction?
Yes, the two terms are used interchangeably to describe reactions where multiple reactants form a single product.
How does a combination reaction differ from a decomposition reaction?
A combination reaction joins two or more substances into one product, while a decomposition reaction breaks one compound into two or more products, the reverse process.