2 Types of Chemical Weathering

Carbonation - one of the most common forms of chemical weathering, rainwater mixes with carbon dioxide in the atmosphere to form a weak carbonic acid (ie acid rain). This acid reacts with certain minerals in the rocks, forcing them to decompose. Rocks such as limestone, with high levels of calcium carbonate, are particularly susceptible to this type of weathering. The carbonic acid reacts with the calcium carbonate to form calcium bicarbonate. This is then dissolved by more rainwater before being removed by solution. If examined closely, it looks like white fizzing foam. It can be found in the Burren, and it can be explained via two chemical equations:

Formulas: 

• H²0 + Co² = H²CO3

• H²C0³ + CaCO³ = Ca(HCO³)²

Hydration and Hydrolysis: while hydration and hydrolysis are two distinct type of processes, they both result from the same action; the addition of water to minerals in a rock. Hydration is where water is absorbed by minerals that do not contain water, forcing minerals to expand and the rock to swell. This increased pressure places a great strain on the rock, forcing it to shatter. It is most prominent in rocks with a high clay content. Hydrolysis on the other hand is the processes whereby hydrogen in water reacts with minerals in the rock, triggering a series of chemical changes. Minerals resistant to hydrogen will slowly start crumbling.