How Am I Supposed to Remember All These Reactions

As you continue to study chemistty, you will encounter a wide variety of chemical reactions. The sheer number of different reactions can seem daunting at times, but most of them fall into a relatively small number of categories. Becoming familiar with several reaction types and learning to recognize patterns of reactivity will help you make sense out of the reactions in this book. Three of the most commonly encountered reaction types are combination, decomposition, and combustion. 

Combination. A reaction in which two or more reactants combine to form a single product is known as a combina-tion reaction. Examples include the reaction of ammonia and hydrogen chloride to form ammonium chloride, 

Decomposition. A reaction in which two or more products form from a single reactant is known as a decomposition reaction. A decomposition reaction is essentially the opposite of a combination reaction. Examples of this type of reaction include the decomposition of calcium carbonate to produce calcium oxide and caibon dioxide gas, 

Combustion. As you learned in Section 3.3, a combustion reaction is one in which a substance bums in the presence of oxygen. Combustion of a compound that contains C and H (or C, H, and O) produces caibon dioxide gas and water. By convention, we will consider the water produced in a combustion reaction to be liquid water. Examples of this type of combustion are the combustion of formaldehyde, 

Although these combustion reactions are shown here as balanced equations, oxygen is generally supplied in excess in such processes to ensure complete combustioa 

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