1. ChemicalWeathering Chemical Weathering

2. Chemical Weathering Chemical weathering - process by which the internal structure of a mineral is altered by the addition or removal of elements.

3. Factors that influence chemical weathering Climate Living Organisms acid production and mineral decomposition Time Mineral composition Chemical Weathering Products Clays Metals ores Rounding of boulders (chemical exfoliation)

4. 1. Carbonation Process by which dissolved carbon dioxide in rainwater forms carbonic acid and reacts with the minerals in the rock. This process weakens the rock thus breaking it down in the process. H 2 0 +C0 2  H 2 C0 3 (water + carbon dioxide  carbonic acid) Most effective agent of chemical weathering: Carbonic acid!

5. 2. Hydrolysis chemical reaction between the minerals in the rock and hydrogen in rain water. For example, during hydrolysis, the feldspar in granite changes to clay mineral which crumbles easily, weakening the rock and causing it to break down.

6. http://www.classzone.com/books/earth_sci ence/terc/content/visualizations/es1202/es 1202page01.cfm?chapter_no=visualizatio nhttp://www.classzone.com/books/earth_sci ence/terc/content/visualizations/es1202/es 1202page01.cfm?chapter_no=visualizatio n

7. 3. Oxidation The process by which oxygen combines with water and minerals in the rock such as calcium and magnesium. When iron reacts with oxygen, reddish - brown iron oxide is formed. The iron-oxide crust crumbles easily and weakens the rock. e.g. : Iron + Oxygen --> Iron Oxide (crumbles)

9. 4. Solution process by which minerals in the rocks dissolve directly in water. Rainwater can dissolve statues and tombstones made of marble (mostly calcite) CaCO 3 + CO 2 + H 2 O  Ca + + 2 HCO 3 - (calcite + carbon dioxide + water  Calcium ion + bicarbonate ion (liquid))

12. Stalactites and Stalagmites Caves and caverns typically form in limestone –stalactites - hang from ceiling –stalagmites - on the ground http://www.goodearthgraphics.com/virtcave/staltite/staltite.html http://www.goodearthgraphics.com/virtcave/stalmite/stalmite.html

13. 5. Hydration process where minerals in the rock absorb water and expand, creating stress which causes the disintegration of rocks. EG: Unhydrated Calcium sulphate + Water --> Hydrated Calcium Sulphate (expands)

14. In text: Page 112 read article 5.1 make notes Finish this web: Page 120 question 12,13,14,15,16