9.3 Reactions of Organic Molecules Combustion The burning hydrocarbons in the presence of oxygen Complete Combustion All the hydrocarbon is used in the reaction. Example with the burning of methane: Incomplete Combustion Occurs when there is a limited amount of oxygen. Example with the burning of methane:

9.3 Reactions of Organic Molecules Types of Reactions Substitution Reactions In a substitution reaction, an atom or group of atoms from a reactant takes the place of an atom or group of atoms on the organic molecule.

9.3 Reactions of Organic Molecules Types of Reactions Addition Reactions An addition reaction occurs when an unsaturated compound becomes saturated. In an addition reaction, electrons in the double or triple bond are shared with a reactant molecule. A triple bond may become a double bond or a double bond may become a single bond

9.3 Reactions of Organic Molecules Types of Reactions Elimination Reactions An elimination reaction is the opposite of an addition reaction. A small molecule such as H2O or HX is eliminated

9.3 Reactions of Organic Molecules Types of Reactions Polymerization The name of a polymer depends on the monomer that it was made from. If the repeating unit is only one monomer, it is called a homopolymer (Figure ). A copolymer contains a mixture of repeating units (Figure ). In Figure , the monomer is shown on the left. When monomers are linked together to produce a polymer, the polymer is represented by showing the monomer in brackets, with the n representing some large number of repeat units.

9.3 Reactions of Organic Molecules Types of Reactions Addition Polymerization You may have heard of polyethylene, one of the most common plastics. It is a polymer made up of repeating units of ethane. To make polyethylene, thousands of ethene molecules are reacted together in a huge addition reaction called “addition polymerization” (Figure ).

Text page Reactions of Organic Molecules Types of Reactions Condensation Polymerization Another way to make polymers is through a condensation reaction. One such polymer is nylon. It is produced when hexamethylenediamine reacts with adipic acid. For each amine that reacts with a carboxylic acid, a water molecule is eliminated. The monomer in nylon-66 has been circled in Figure