Chapter Two: Types of Chemical Reactions

In different reactions atoms or ions rearrange themselves in different ways. There are three types of reactions: Synthesis (combination), Decomposition, Displacement (single or double).

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Synthesis (combination reactions)

In chemical laboratories, as well as in industry, synthesis reactions are used to produce new substances from simpler substances.A and B are elements or compounds and AB is a complex compound. This reaction gives off energy. This type of reaction is represented by the following equation:

A + B gives AB

Decomposition Reactions

The decomposition of most pure substances takes place when energy is used. This type of reactions is represented by the general equation:

AB gives A + B

Displacement Reactions
a) Single displacement reactions: The general equation for this reaction is

A + BC gives AB + C

b)Double Displacement reactions: The general equation for this type of reaction is

AB + CD gives AD + CB

Question: What do you think makes Displacement reactions exothermic?