Chemical Reactions by What Atoms Do

In this alternative way of classifying reactions, we focus on the pattern of the reaction by classif ung it into one of the following four categories. In this classification scheme, the letters (A, B, C, D) represent atoms or groups of atoms. 

SYNTHESIS OR COMBINATION REACTIONS. In a synthesis or combination reaction, simpler substances combine to form more complex substances. The simpler substances may be elements, such as sodium and chlorine combining to form sodium chloride. 

The simpler substances may also be compoxmds, such as calcium oxide and carbon dioxide combining to form calcium carbonate. 

In either case, a synthesis reaction follows the general equation  

A In a synthesis reaction, two simpler substances combine to make a more complex substance. In this series of photographs we see sodium metal and chlorine gas. When they combine, a chemical reaction occurs that forms sodium chloride. 

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