Chemical weathering takes place in almost all types of rocks. Smaller rocks are more susceptible, however, because they have a greater amount of surface area.
Chemical reactions break down the bonds holding the rocks together, causing them to fall apart, forming smaller and smaller pieces. Chemical weathering is much more common in locations where there is a lot of water. This is because water is important to many of the chemical reactions that can take place. Warmer temperatures are also more friendly to chemical weathering. The most common types of chemical weathering are oxidation, hydrolysis and carbonation.
Oxidation takes place when oxygen combines with other elements in rocks to form new types of rock. These new substances are usually much softer, and thus easier for other forces to break apart.
Hydrolysis occurs when water combines with the substances in rocks to form new types of substances, which are softer than the original rock types. This allows other forces, such as mechanical weathering, to more easily break them apart.
Carbonation takes place when carbon dioxide reacts with certain types of rocks forming a solution that can easily be carried away by water.