January 27 - Types of Chemical Reactions

So today we learned about 3 types of chemical reactions : Synthesis, Decomposition, and Single Replacement.

Synthesis:  A synthesis reaction is when two or more simple compounds combine to form a more complicated one. These reactions come in the general form of: A + B --> AB


Eg. 8 Fe + S₈ ---> 8 FeS


Decomposition:A decomposition reaction is the opposite of a synthesis reaction - a complex molecule breaks down to make simpler ones. These reactions come in the general 
form: AB --> A + B


Eg.2 H₂O ---> 2 H₂ + O₂




Single Replacement:This is when one element trades places with another element in a compound. These reactions come in the general form of: A + BC ---> AC + B


Eg. Mg + 2 H₂O ---> Mg(OH)₂ + H₂


Ask these questions to figure out which type of chemical reaction it is:

1. Does your reaction have two (or more) chemicals combining to form one chemical? If yes, then it's a synthesis reaction.

2. Does your reaction have one large molecule falling apart to make several small ones? If yes, then it's a decomposition reaction.

3. Does your reaction have any molecules that contain only one element? If yes, then it's a single replacement reaction.