# AP Chemistry : Addition and Decomposition Reactions

## Example Questions

### Example Question #4 : Types Of Reactions

The reaction above could be classified as __________.

decomposition and oxidation-reduction

decomposition

oxidation-reduction

synthesis

single displacement

decomposition

Explanation:

When one molecule is converted into two or more smaller molecules, the reaction is considered a decomposition reaction. In this example, none of the elements under go a change in oxidation number, so this is not an oxidation-reduction reaction. (Calcium is always , oxygen is always , and carbon remains  throughout the reaction.)

### Example Question #1 : Fundamental Reaction Concepts

Which of the following represents a combustion reaction?

Explanation:

Combustion reactions always produce  and excess heat. Depending on the molecule that is oxidized by oxygen, which in this case was methane , the ratios between  and  can vary.