11.2. Types of Chemical Reactions http://www.ck12.org
Combustion
Combustionoccurs when a hydrocarbon reacts in the presence of oxygen to produce water and carbon dioxide.
These reactions are very exothermic, which means that they produce a large amount of heat. Combustion reactions
are quite common in our everyday lives, such as the burning of gasoline to fuel a car. The chemical equation for a
combustion reaction has the following generic form:
CxHy+O 2 →H 2 O+CO 2
FIGURE 11.9
Combustion reaction of a marshmallow
(sucrose) and wood (cellulose).The process of cellular respiration can be thought of as a highly controlled version of a combustion reaction. We do
not literally burn hydrocarbons in our body, but the overall reactants and products are the same. Hydrocarbons, such
as sucrose (C 12 H 22 O 11 ), are combined with oxygen in a series of enzymatic steps to product water, carbon dioxide,
and energy, which is stored in the form of reactive molecules. The unbalanced chemical equation for this overall
process is shown below:
C 12 H 22 O 11 +O 2 →CO 2 +H 2 O
Lesson Summary
- Combination reactions occur when two or more reactants combine to produce a single compound.
- Decomposition reactions involve one compound decomposing into two or more products.
- Single replacement reactions occur when one reactant replaces part of another compound to form new sub-
stances. - A common type of double replacement reaction occurs when two ionic reactants exchange anions, making
two new ionic compounds. The precipitation of a solid is a common result for this type of reaction. - Combustion reactions involve the reaction of a hydrocarbon with oxygen gas to produce water and carbon
dioxide.