A chemical reaction happens when substances are added together and a totally new product (or products) are formed. In this section we are going to look at the types of chemical reaction and how to tell when they are finished.                                                                      Below is a list of some of the types of reaction[i]. You really need to know these as they will be referred to constantly in the rest of the book. 

Exothermic:

A reaction that gives out energy -think “ex” as in exit.

Endothermic:

A reaction that takes in heat from the surroundings – think “en” as in enter.

Combustion Reaction:

Burning something to produce new substances

Precipitation Reaction: 

Reacting two solutions (liquids with something dissolved in it) together and producing a solid product. 

There are three ways you can tell that a chemical reaction has taken place. These are:

·         Bubbles, which means that a gas has been released.

·         A colour change.

·         A precipitate (solid) is formed.