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http://quizlet.com/2640747/ib-chemistry-acid-deposition-sl-hl-flash-cards/. http://www.chemistry.wustl.edu/~edudev/LabTutorials/Water/FreshWater/acidrain.html. http://www.chemistry.wustl.edu/~edudev/LabTutorials/Water/FreshWater/acidrain.html. What is Rain.
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http://quizlet.com/2640747/ib-chemistry-acid-deposition-sl-hl-flash-cards/http://quizlet.com/2640747/ib-chemistry-acid-deposition-sl-hl-flash-cards/ • http://www.chemistry.wustl.edu/~edudev/LabTutorials/Water/FreshWater/acidrain.html
http://www.chemistry.wustl.edu/~edudev/LabTutorials/Water/FreshWater/acidrain.htmlhttp://www.chemistry.wustl.edu/~edudev/LabTutorials/Water/FreshWater/acidrain.html
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: CO2(g) + H2O(l) => H2CO3(aq)
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.
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) • sulfur dioxide (combustion of fossiul fuels or smelting of sulfide ores) • nitrogenmonoxide(internal combustion engines) and nitrogen dioxide gases in the atmosphere, combine with water vapor and precipitate as sulfuric acid or nitric.
Formation of Sulfuric Acid(H2SO4) S(s) + O2(g) => SO2(g) 2SO2(g) + O2(g)(air) 2SO3(g) SO3(g) + H2O(l)(rain)H2SO4(aq) Formation of Nitric Acid(HNO3) N2(g)+ O2(g) => 2NO(g) (engines,high T) 2NO(g) + O2(g) (air)2NO2(g) 2NO2(g) + H2O(l)(rain) HNO3(aq)+HNO2 (aq) directly producing nitric acid in water.
Sources OF ACID RAIN SO2 NOX
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
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 SO2 and NO), are deposited on, or absorbed onto, surfaces.
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.
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
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
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
Effects of Acid Rain on Vegetation http://abacus.bates.edu/~ganderso/biology/bio270/clover_leaf_burns_pH2_30d.gif MSN Encarta
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 MSN Encarta http://www.lauraknauth.com/photos/france/thinker.jpg
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.
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
Preventive Measures • Use cleaner fuels • Coal that contains less sulfur • "Washing" the coal to reduce sulfur content • Natural Gas
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
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
Preventive Measures • Use sources other than coal to generate electricity • Issue of cost • nuclear power • hydro-electricity • wind energy • geothermal energy, • solar energy http://upload.wikimedia.org/wikipedia/commons/4/4e/Nuclear_Power_Plant_Cattenom.jpg
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