Two forms of chemical weathering

chemical weathering is the corrosion/ decomposition of rocks due to chemical reaction between their minerals water and air in the atmosphere. Some minerals are dissolved while others are chemically changed

• Carbonation- Rain water mixes with carbon dioxide in the atmosphere to form a weak carbonic acid.

• this acid reacts with certain minerals forcing rocks to decompose.

• Rocks such as limestone have a high level of calcium carbonate and are particularly susceptible.

• The carbonic acid reacts with the calcium carbonate to form calcium bicarbonate.

• this is then dissolved by more rainwater before in being removed in solution.

• the chemical reaction can be seen as a white fizzing foam.

• can be seen in the burren

  H₂O+CO₂=H₂CO₃

  H₂CO₃+CaCO₃=Ca(HCO₃)₂

• Hydration and Hydrolysis- Even though the two distinct 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 causing the rock to swell.

• This increased pressure strains until rock eventually to shatter most prominent in rocks with high clay content.

• Hydrolysis is the process whereby hydrogen in water minerals in water reacts with minerals triggering chemical changes.

• minerals resistant to hydrolysis will slowly rock crumbling