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Weathering

Weathering. Grade 9 2012-2013 Prepared by teacher: Ronak Ahmed Duhok International School. Chemical weathering. The process by which rocks break down as a result of chemical reactions. What is the meaning of Chemical Weathering?. The common agents of chemical weathering are: Water

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Weathering

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  1. Weathering Grade 9 2012-2013 Prepared by teacher: Ronak Ahmed Duhok International School

  2. Chemical weathering The process by which rocks break down as a result of chemical reactions What is the meaning of Chemical Weathering? The common agents of chemical weathering are: Water Weak acids air

  3. Some examples of chemical weathering

  4. water Hard rock, such as granite It can be broken down by water. But it just may take thousands of years

  5. Acid Precipitation Acids Rain, or snow, that contains a high concentration of acids is called acid precipitation

  6. Some effects of acid precipitation

  7. If the precipitation contain more acids than the normal precipitation. Precipitation is naturally acidic. So when the rain will be acidic rain?

  8. What will the high level of acidity can cause? very rapid weathering of rock. Could acid precipitation caused by natural sources? Yes, small amount of sulfuric and nitric acids from natural sources, such as volcanoes, will cause acid precipitation

  9. Other causes of acid rain is air pollution from the burning of fossil fuels, such as coal & oil.

  10. How acid rain is formed from burning of fossil fuels? • When these fuels are burned, they give off gases including sulfuric oxides (SOx), nitrogen oxides (NOx), and carbon oxides (CO). • When these compounds combine with water in the atmosphere, they form acids, which then fall back to the ground in rain & snow. When acid precipitation could be harmful to plants & animals? When the acidity is too high

  11. Acids in groundwater In certain places (such as Jeita cave), ground water contains acids, such as carbonic or sulfuric acid. When groundwater comes in contact with limestone, a chemical reaction occurs. Over along period of time, the dissolving of limestone forms karst features, such as caverns Formed from eating away of the limestone

  12. Acids in living things How lichens affect on rocks? Lichens produce acids that can slowly break down rock Where can lichens grow? • They grow on the side of trees or rocks. • Also grow in places where some of the hardiest plants cannot. • Ex: in desert, arcticarea, and in area high above timberline in mountain ranges.

  13. Air How cars undergoing chemical weathering? It is undergoing chemical weathering due to the oxygen in air…….HOW??? The oxygen in the air is reacting with the iron in the car, causing the car to crust. Speeds up the process. What is the role of water in crusting cars? But the iron would rust even if no water were present. Scientists call this process oxidation.

  14. What is the definition of oxidation Is a chemical reaction in which an element, such as iron, combines with oxygen to form an oxide. This common form of chemical weathering is what causes rust. Give examples for things can experience oxidation. Old cars Aluminum cans Your bike If left exposed to air & rain for long periods of time When?

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