Acid Rain and Organic Chemistry. Chemistry part 2

Transcription

1 Acid Rain and Organic Chemistry Chemistry part 2

2 Two main factors affect the amount of acid precipitation 1) The amount of NOx and SOx emissions locally

3 2. Prevailing wind directions Wind patterns like the Jet Stream tend to push acid clouds toward Northern Ontario and Northern Quebec

4 The type of soil has a big impact on the damage done by acid rain. Alberta has mainly sedimentary deposits which is rich in natural buffer compounds such as CALCIUM CARBONATE (CaCO 3 ) Carbonate ions react with hydronium ions helping to prevent the soil`s ph from dropping

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6 Carbonate ions in the soil act as a buffer Alberta s soil is alkaline in most regions due to the presence of carbonate. Acid rain on limestone (calcium carbonate rock)

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8 A Buffer Reaction The arrows pointing left and right mean the reaction can go in either direction

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10 hydrogen carbonate acts as a buffer in human blood in a way similar buffering in Alberta s soils

11 Plant Effects Low ph levels can hamper plant growth Acid can leach important plant nutrients from the soil, such as nitrates, phosphates and potassium

12 Some metal ions become soluble at low ph s One of these is aluminum ions which cause decreased root growth decreased absorption of calcium by roots kills important bacteria that help to release nutrients in the soil

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14 Root growth stunted by aluminum ions leeched from soil be acidic water

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16 Effects on Animals Low ph can kill animal (such as fish) directly Fish hatchlings are more sensitive to low ph Acid can dissolve or soften the shells of some organisms Aluminum ions cause excessive mucous production in fish gills, which can lead to suffocation

17 Acid can also leach other toxic metal ions such as, mercury and lead Because these metal ions are not removed from the tissue of animals in the food chain, the concentration builds up in each trophic level.

18 The tendency for a pollutant to become concentrated at higher levels in a food chain Biomagnification

19 SOLUTIONS TO THE PROBLEM OF ACID RAIN

20 SOLUTIONS TO THE PROBLEM OF ACID RAIN The old approach: build stacks tall enough that the effects spread over a greater area and become insignificantly small. This did not work. New approach: reduce the emission of NOx(g) and SOx(g)

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22 Stack (380 m) at Sudbury nickel refinery, used to disperse SO x gases

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25 Effect of acid rain on a forest, Jizera Mountains, Czech Republic

26 New technologies have been developed to catch the emissions before they are released. ELECTROSTATIC PRECIPITATORS use electric forces to remove fly ash from coalfired power plant stacks (NOx and SOx can stick to fly ash particles)

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28 Coal burning power plants Sulphur compounds are common in some coal deposits Can contain more than 5% sulfur Coals in Alberta are generally low in sulphur and therefore burn cleaner than coals found elsewhere around the world.

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31 SCRUBBERS can also be used to remove NOx and SOx from gas being emitted from power plants or other industrial processes

32 A 360 ton scrubber to help cut a power plant's pollution by 84 percent

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34 the cost of adding scrubbers to old small plants to meet pollution limits would make them too expensive to run. makes sense to shut down old plants when prices are low.

35 new vehicles have CATALYTIC CONVERTERS to remove NOx from vehicle exhaust.

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38 PHOTOCHEMICAL SMOG

39 A major component of smog is groundlevel (or tropospheric ) ozone O 3 (g) which is caused by photochemical reactions involving energy from sunlight

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41 Ozone irritates and damages the lungs and can cause premature death in people with respiratory illnesses like asthma and cystic fibrosis

42 Ozone also inhibits photosynthesis in plants

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44 Another dangerous component of smog is PAN (peroxyacetyl nitrate) It is a strong irritant to the lungs It results from the reaction of NOx with O 3 and VOCs (volatile organic compounds)

45 PAN PAN becomes an issue when ethanol is used as an automotive fuel carrier for NOx into rural regions and causes ozone formation near the surface

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47 ALTERNATIVE ENERGY SOURCES Alternative energy technologies decrease the emissions of NOx and SOx by decreasing fossil fuel combustion

48 LEGISLATION Governments play a large role in preventing air pollution by setting laws and regulations

49 ORGANIC CHEMISTRY AND THE ENVIRONMENT Organic chemistry is the study of complex, carbon-based molecules Organic compounds make up or come from living things Carbonate (CO 3-2 ), CO 2, CO and cyanides (CN - ) compounds are not considered organic

50 Because carbon has four valence electrons, it can bond to four other atoms It forms COVALENT bonds involving the sharing of electrons

51 Simplest organic molecule is methane (also known as natural gas)

52 The ball-and-stick model shows the position of atoms and the locations of bonds

53 Space-filling models show the space occupied by each atom (including its electrons)

54 Because carbon can bond to 4 other atoms, it can form an almost infinite variety of structures

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57 Molecular Models Assignment Construct the following table. Build each molecule using the description. Organic Compound Description Drawing of Structure Chemical Formula Source/Use/Issue Methane (Natural Gas) A single carbon bonded to 4 hydrogen atoms CH 4 Combusted in my house s furnace A potent greenhouse gas Propane A chain of three carbons connected by single bonds Ethyne (aka acetylene) Two carbons connected by a triple bond Ethanol 2 carbons with a hydroxyl group (R-OH) Benzene A six carbon ring. Each carbon has only 1 hydrogen

58 SIMPLE CARBON CHAINS The simplest organic compounds are called HYDROCARBONS Hydrocarbons are made up of carbon and hydrogen They are the main components of fossil fuels

59 The oil is refined separated in different products used for different purposes

60 The main component of gasoline is simple carbon chain called OCTANE (C 8 )

61 ALKANES Hydrocarbon chains that have only single bonds # of Carbons Name Structure 1 Methane CH 4 2 Ethane CH 3 CH 3 3 Propane CH 3 CH 2 CH 3 4 Butane CH 3 (CH 2 ) 2 CH 3 5 Pentane CH 3 (CH 2 ) 3 CH 3 6 Hexane CH 3 (CH 2 ) 4 CH 3 7 Heptane CH 3 (CH 2 ) 5 CH 3 8 Octane CH 3 (CH 2 ) 6 CH 3 9 Nonane CH 3 (CH 2 ) 7 CH 3 10 Decane CH 3 (CH 2 ) 8 CH 3

62 Structural Formulas

63 Because alkanes only have single bonds between carbons, they have the maximum number of hydrogen atoms, and are called SATURATED

64 Unsaturated hydrocarbon chains have one or more double bonds between carbons This results in fewer hydrogen atoms, so are called unsaturated Unsaturated fats are easier for enzymes to break down

65 ALKENES Hydrocarbon chains that have one or more double bonds. Ethene: 2 carbons with a double bond

66 Propene: 3 carbons with a double bond

67 But-1-ene: 4 carbons, double bond after the 1 st carbon

68 Bonds are after carbon 1 and carbon 3 but-1,3-diene 4 carbon chain: but Double bond: -ene 2 double bonds: diene

69 ALKYNES Hydrocarbon chains that have one or more triple bonds. H C C CH 3 propyne CH 3 CH 2 C C CH 2 CH 3 hex-3-yne

70 Branched Alkanes pentane butane methyl Methyl butane

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73 Methyl butane 3-ethyl-2-methylhexane

74 2,3,5-trimethylhexane

75 Example Determine the name of 2,2,4 trimethylpentane