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 reshWater/acidrain.html.

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Presentation on theme: " reshWater/acidrain.html."— Presentation transcript:

1 http://quizlet.com/2640747/ib-chemistry-acid-deposition-sl-hl-flash-cards/  http://www.chemistry.wustl.edu/~edudev/LabTutorials/Water/F reshWater/acidrain.html http://www.chemistry.wustl.edu/~edudev/LabTutorials/Water/F reshWater/acidrain.html

2  http://www.chemistry.wustl.edu/~edud ev/LabTutorials/Water/FreshWater/acidr ain.html http://www.chemistry.wustl.edu/~edud ev/LabTutorials/Water/FreshWater/acidr ain.html

3 What is Rain  Rain is usually acidic, ph 5.65, because it  dissolves and  reacts with carbon dioxide as it falls through the air.  Carbon dioxide forms a weak acid in water: CO 2 (g) + H 2 O(l) => H 2 CO 3 (aq)

4  Acid deposition refers to the process by which acidic particles, gases and  precipitation leave  the atmosphere,  There are two types of acid deposition:  Wet and Dry.

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6 Acid Rain  Acid Rain is a type of wet deposition, precipitation(rain, snow, hail) that has a pH lower than 5.6  It is formed when(sulfur& nitrogen oxides) 1. sulfur dioxide (combustion of fossiul fuels or smelting of sulfide ores) 2. nitrogen monoxide(internal combustion engines) and nitrogen dioxide gases in the atmosphere, combine with water vapor and precipitate as sulfuric acid or nitric.

7 Formation of Sulfuric Acid (H 2 SO 4 ) S(s) + O 2 (g) => SO 2 (g) 2SO 2 (g) + O 2 (g)(air)  2SO 3 (g) SO 3 (g) + H 2 O(l)(rain)  H 2 SO 4 (aq) 2NO(g) + O 2 (g) (air)  2NO 2 (g) 2NO 2 (g) + H 2 O(l)(rain)  HNO 3 (aq)+HNO 2 (aq) directly producing nitric acid in water. Formation of Nitric Acid (HNO 3 ) N 2(g) + O 2 (g) => 2NO(g) (engines,high T)

8 Sources OF ACID RAIN SO 2 NO X

9 Sources of Acid Rain //www.youtube.com/watch?v=RP-sU8i2edo&feature=fvst  The principal cause of acid rain is from human sources Cars,vehicles,nitrogen monoxide Industrial factories, power-generating plants and vehicles Sulfur dioxide and oxides of nitrogen are released during the fuel burning process (i.e. combustion) Sulfur dioxide accounts for about 90 % of all acid rainfall MSN Encarta

10 Formation of Acid Rain

11 Acidic Rain Deposition Acidic particles and vapors are deposited via two processes - wet and dry deposition. Wet deposition is acid rain, the process by which acids with a pH normally below 5.6 are removed from the atmosphere in rain, snow, sleet or hail. Dry deposition takes place when particles such as fly ash, sulfates, nitrates, and gases (such as SO 2 and NO), are deposited on, or absorbed onto, surfaces.

12 http://myecoproject.org/get-involved/pollution/acid-rain/  Acid rain often precipitates miles away from its source.  Causes damages to building materials (carbonates).  Affects vegetation by leaching minerals from soil.  Affects aquatic life by altering pH of  rivers.( below 4, dead)  Affects human health by increasing respiratory diseases.

13  Buildings made of stone become  corroded, as the sulfuric acid in acid  rain reacts with the calcium carbonate  to form _____, which can be washed  away

14 Harmful Effects of Acid Rain  Harmful to aquatic life Increased acidity in water bodies Stops eggs of certain organisms (e.g. fish) to stop hatching  Changes population ratios  Affects the ecosystem

15 Effects of Vegetation  Harmful to vegetation Increased acidity in soil Leaches nutrients from soil, slowing plant growth Leaches toxins from soil, poisoning plants Creates brown spots in leaves of trees, impeding photosynthesis  Allows organisms to infect through broken leaves

16 Effects of Acid Rain on Vegetation MSN Encarta http://abacus.bates.edu/~ganderso/biology/bio270/clover_leaf_bu rns_pH2_30d.gif

17 Effects of Acid Rain on Buildings and Structures  Marble is particularly susceptible  Accelerates weathering in metal and stone structures Eg. Parthenon in Athens, Greece; Taj Mahal in Agra, India http://www.lauraknauth.com/photos/france/thinker.jpgMSN Encarta

18 Effects of Acid Rain on Human Health  Affects human health Respiratory problems, asthma, dry coughs, headaches and throat irritations Leaching of toxins from the soil by acid rain can be absorbed by plants and animals. When consumed, these toxins affect humans severely. Brain damage, kidney problems, and Alzheimer's disease has been linked to people eating "toxic" animals/plants.

19 Preventive Measures  Reduce amount of sulfur dioxide and oxides of nitrogen released into the atmosphere Use less energy (hence less fuel burned) Use cleaner fuels Remove oxides of sulfur and oxides of nitrogen before releasing  Flue gas desulphurization  Catalytic Converters

20 Preventive Measures  Use cleaner fuels Coal that contains less sulfur "Washing" the coal to reduce sulfur content Natural Gas

21 Preventive Measures  Flue Gas Desulfurization (FGD) Removes sulfur dioxide from flue gas (waste gases) Consists of a wet scrubber and a reaction tower equipped with a fan that extracts hot smoky stack gases from a power plant into the tower Lime or limestone (calcium carbonate) in slurry form is injected into the tower to mix with the stack gases and reacts with the sulphur dioxide present

22 Preventive Measures  (continued) Produces pH-neutral calcium sulfate that is physically removed from the scrubber Sulfates can be used for industrial purposes Scrubber at work MSN Encarta

23 Alkaline Scrubbers

24 Preventive Measures  Use sources other than coal to generate electricity  Issue of cost http://upload.wikimedia.org/wikipedia/commons/4/4e/Nuclear_Power_Plant_Cattenom.jpg nuclear power hydro-electricity wind energy geothermal energy, solar energy

25 Reducing the effects of Acid Rain  Liming Powdered limestone/limewater added to water and soil to neutralize acid Used extensively in Norway and Sweden Expensive, short-term remedy


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