 Two or more substances combine to make one new substance  General Formula  A + B → AB  Characteristic Has one product

 One compound breaks down into two or more simpler substances  General Formula AB  A + B  Characteristics Only have one reactant Can have two or more products

 One element replaces another element in a compound  General Formula  AB + C  AC + B orAB + D  BD + A A and C are positive ions B and D are negative ions  Characteristics Has a single element and a compound in both the reactants and products.

 An exchange of positive ions between two compounds  General Formula AB + CD → AD + CB  Generally take place in aqueous solution

 A hydrocarbon combines with oxygen to produce carbon dioxide and water.  General Formula Hydrocarbon + O 2  CO 2 + H 2 O  Characteristics Products are always carbon dioxide and water