These are the illustrations and the examples of the chemical formulas for the 4 different chemical reaction types.

 

1.  Synthesis

A+B -> AB

Na + Cl2 -> NACl

2Na + Cl2 -> NaCl

 

2. Decomposition

AB -> A + B

H2O -> H2 + O2

2H2O -> 2H2+O2

 

3. Single Replacement

A + BC -> AC + B

Al + CuCl2 -> Cu + AlCl3

2Al + 3CuCl2 -> 3Cu + 2AlCl3

 

4. Double Replacement

AB+CD -> AC+BD

CaS + NaOH -> CaOH2 + NaS2

CaS + 2NaOH -> CaOH2 + NaS2