A chemical reaction occurs when two substances are mixed in their solid state. Iodine and sulphur react explosively when brought into close contact. A chemical reaction occurs when two substances are mixed in the solution form Sodium carbonate and tartaric acid vigorously react only in the solution state.

Chemical reactions can be identified via a wide range of different observable factors including change in color, energy change (temperature change or light produced), gas production, formation of precipitate and change in properties.

A synthesis reaction is a type of reaction in which multiple reactants combine to form a single product. Synthesis reactions release energy in the form of heat and light, so they are exothermic. An example of a synthesis reaction is the formation of water from hydrogen and oxygen.

Table of Contents Types of Chemical ReactionsExplanationGeneral ReactionCombination reactionTwo or more compounds combine to form one compound.A + B → ABDecomposition reactionThe opposite of a combination reaction – a complex molecule breaks down to make simpler ones.AB → A + B4 more rows

Two different ways to classify chemical reactions presented in Section 7.10 are by the type of reactants and by the type of products.

Most chemical reactions can be classified into one or more of five basic types: acid–base reactions, exchange reactions, condensation reactions (and the reverse, cleavage reactions), and oxidation–reduction reactions.