Chemical weathering is the breakdown of rocks, minerals, and soils by chemical reactions. The two most important causes of chemical weathering are:

- Water: Water is the most important agent of chemical weathering. It can dissolve minerals, break down rocks, and transport weathered material away.

- Acids: Acids, such as carbonic acid (H2CO3), can dissolve minerals and break down rocks. Carbonic acid is formed when carbon dioxide (CO2) from the atmosphere dissolves in water.