Forms of chemical weathering
Answer Text: Chemical Weathering- Involves various chemical reaction which takes place between rock water and certain atmospheric gases like oxygen and carbon dioxide- Dominant in humid climates where water is abundant and temperature are- Weathering involving changes in the chemical composition of minerals making up rocks- It takes place in the following five ways/ processes:a) Solution- Break up of rocks as a result of dissolving of minerals in water without chemical change in them.- Rain water falls on rocks with soluble minerals.- The minerals are dissolved and carried down in solution.–The rock gets weakened and crumbles.b) Carbonation- Weathering caused by reaction of calcium carbonate in rocks with rainwater containing a weak carbonic acid.- Common in temperate regions.- Rain water absorbs small quantities of carbon dioxide forming a weak carbonic acid.#H_2O+CO_2toH2_CO_3#- The weak carbonic acid falls on limestone rocks reacting with them forming calcium bicarbonate.#CaCO_3+H_2CO_3toCa (HCO_3)#- Calcium bicarbonate is removed from the rock in solution.c) Hydrolysis- Weathering caused by reaction of hydrogen ions of water and ions of rock minerals.- Igneous rocks are greatly affected.d) Oxidation- Weathering in which minerals in rocks combine with oxygen in the presence of moisture to form new minerals.- Rocks containing iron are affected.- Ferric oxide is formed on the rock surface which appears as a soft brown or red earth which can be scooped by hands.e) Hydration- It is absorption of water by rock.- Weathering in which hygroscopic minerals in rocks take up water causing them to swell and expand causing disintegration of rock due to internal stress.- It occurs alongside other process.
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