Chemical weathering: The break up of rocks by processes such as solution causing changes in the minerals that form the rock
The chemical break down of rocks is mainly due to rocks being dissolved in rain water. This absorbs carbon dioxide in the air to form weak carbonic acid. Futhermore air pollution adds to the acidity of the water, increasing it's ability to attack rocks. This is called solution weathering.
The chemical formular for limestone solution is
CaCO3 +H2O + CO2 ----> Ca(HC03)2
calcium carbonate+ water+ carbon dioxide -----> calcium bicarbonate
This process happens very slowly it can take carbonic acid 100,000 years to weather 45cm of Limestone. Chemical weathering is most effective in hot, humid conditions wear reactions happen faster.
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