2H2O 2H2 O2. One way to think of synthesis reactions is that they are the reverse of a decomposition reaction. Chemical Reactions Combination Decomposition Combustion Single Double Displacement Chemistry Youtube The Cl is diatomic that explains the 2. . 2NaCl - 2Na Cl_2- The NaCl was broken down into the constituents Na and Cl_2---side note. Two reactants are combining and form one product. Read additional examples at Wikipedia. An example is the burning of charcoal carbon in excess oxygen to make carbon dioxide. Find step-by-step Anatomy and physiology solutions and your answer to the following textbook question. Practically synthesis is opposite of decomposition. The newly formed product is always a compound while the reactants can be elements or compounds. A synthesis reaction is a reaction in which two or more reactants combine to form a more complex substance. In a synthesis reaction bonds are formed ...