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Chem 321 > Chem Quiz 2 > Flashcards

Chem Quiz 2 Flashcards

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1
Q

What is CO2 sequestration?

A

To be sequestered is to be deposited underground or an ocean location that would prevent its release into the air.

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2
Q

What is the Automatic 3 way converter?

A

A three stage catalytic converter that changes nitrogen oxides back into elemental nitrogen and oxygen using unburned hydrocarbons and the combustion intermediates CO and H2 as reducing agents

80-90% removal of hydrocarbons, CO, and NOx from automobile exhaust.

2NO —> N2 +O2

Also reduces SO2 to H2S

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3
Q

The Gothenburg protocol calls to reduce ____ emissions by 40% by 2010

A

NOx

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4
Q

What is SO2 acid rain?

A

Atmospheric precipitation of substantial amounts of acids, significantly more acidic than natural rain, where unpolluted rain has a pH of 5.6 (b/c carbonic acid is in rain)

Coincides with major city centres. The east coast of USA has lost of agriculture = lost of acid rain

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5
Q

SO2 and power plants

A

Power plants are often builds with tall smoke tacans which disperse plume over a large area. This plume of SO2 particulate matter causes acid rain

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6
Q

SO2 and gasoline/diesel fuel

A

Maximum sulphur levels in gasoline are 30ppm in the US and Canada

Sulphur is removed from gas during refining through HYDROSULFRICATION

The catalytic process which reacts or gaining sulphur-contains molecules with H2 to make H2S

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7
Q

How can we reduce SO2 emissions?

A

1) limit use of sulphur content in fuels
2) remove sulphur from stack gases (coal fired power plants)

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8
Q

What is the most obvious form of pollution?

A

The black smoke coming from diesel trucks

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9
Q

What is particulate matter?

A

Tiny particles suspended in air that form a haze (0.1-1um)

Settle under the influence of gravity: stokes law. All suspended particles are falling, just slowly

Small particle stay suspended in air almost indefinitely if not removed by rain

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10
Q

What is the diameter of particulates

A

Individual particles can be coarse or fine, depending on if they are larger or less than 2.5 um

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11
Q

What is tropospheric aerosol

A

A collection of particulates dispersed in air (with a diameter less than 100 um) that have negligible fall speeds

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12
Q

Coarse particulates

A

Greater than 2.5 um
Originate from natural sources
Mostly primary
Sea spray particles, soil dust from rocks, debris from natural fires, pollen, leaf litter particles

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13
Q

Fine particulates

A

Less than 2.5 um
Formed mainly by chemical reactions between gases and coagulation of smaller molecules
Mostly secondary
Natural and anthropogenic sources

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14
Q

What is the sulfate layer

A

Much of the sulphur in the air is from dimethyl sulfide emitted from oceans, which is then oxidized to SO2 in the troposphere
SO2 is oxidized to H2So4 in the stratosphere, which creates the sulfate layer

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15
Q

the effect of NH3 on the atmosphere

A

NH3 is released from biological decay, livestock, and use of fertilizers
NH3 is produced in a reaction between urea and water
From this, (NH4)SO4 is also released into teh atmosphere, which then neutralizes acid rain. Which is also why precipitation over the central US is not acidic

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16
Q

What are primary particulates

A

Directly released into the atmosphere
Carbonaceous aersols (organic matter, black carbon)
Industrial dust
Sea spray (course)
Mineral (soil) dust (coarse)

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17
Q

What are the anthropogenic origins of primary particulates

A

Tires, vehicle brakes, metal smelting, vehicle exhaust, soot

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18
Q

What is soot

A

Crystallites of carbon form incompletely combustion

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19
Q

Roughly 50% of heavy duty diesel vehicle exhaust is__________________________

A

carbon based primary atmospheric fine particulates

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20
Q

What is sea spray

A

Primary particulate
Coarse
Above oceans or can be blown onto land
High concentration of NaCll because sea spray leaves NaCl particles airborne

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21
Q

What is the purpose of Mineral dust ?

A

Minerals have a chemical composition to that of the earth’s crust, so they are basic and can neutralize acid rain when particulates enter the atmosphere

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22
Q

What are secondary particles ?

A

Formed in the atmosphere (in situ)
Suphates
Nitrates
Organic compounds

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23
Q

What is an Aiken nuclei?

A

A microscopic aerosol particle in the atmosphere that encourages condensation to gather into a. Droplet (cloud nucleation)

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24
Q

What is the PM index?

A

The particulate matter index
The measure of suspended particles in the air
Shows the amount of particlaute matter per volume (ug/m^3)
Smaller particles have a greater detriment to humans
PM10 and PM2.5

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25
Particulate matter has a ______ effect on humans than pollutant gases
Greater
26
What is PM10
Particulate matter 10 micrometers or less in diameter Inhale-able particles Typically 20-30 ug/m^3 in an urban area More coarse, will irritate your eyes, nose and throat
27
What is PM2.5?
Particulate matter 2.5 micrometers or less in diameter Respirable particles that penetrate deep into the lungs (10-13ug/m^3P), strongly correlated with increase rate of disease/ mortality Fine particles Can get into lungs and blood
28
Why are larger particles of less health concern to humans?
They settle quicker, exposer is reduced Coarse particles can get filtered by hair and throat They have a much smaller surface area than smaller particles
29
How does engine exhaust relate to PM 2.5
Exhaust from diesel engines has been classified as likely to be a carcinogenic to humans
30
___% increase in a city’s mortality rate for every ___ increase in the PM 2.5 index
3% 5ug/m^3
31
What are the USA environmental distorts in the 60s and 70’s
62 — Rachel Carson published silent spring about DDT (insecticide 69 — cayahoga river in Cleveland Ohio caught on fire Mid 70s — the love canal
32
What is the EPA?
US. Environmental protection agency, founded in 1970
33
What are the pollution control programs?
Clean Air (1970) and Water (1972) Acts Compensation and liability act (superfund act “End-of-pipe-solutions” US pollution prevention act (1990)
34
What are the Clean Air and Water Acts ?
Attempt to control the release of toxic and harmful chemicals into the environment
35
What is the love canal neighbourhood?
‣ Built in Niagara Falls on a chemical dump ‣ 22,000 tons of assorted chemicals including the pesticide lindane, chlorobenzenes, chlorinated hydrocarbons, benzene, chloroform, trichloroethylene,methylene chloride, benzene hexachloride, polychloronated biphenyls (PCB’s) ‣ After the rainy season, the toxic waste began to seep into and build up in the neighbourhood basements. Drums of waste chemicals surfaced ‣ This site was on the superfund list in 2004, and cost 400 million to clean up
36
What is the compensation and liability act?
The superfund act set up procedures and fund for cleaning up toxic waste sites (of which there are over 1000 in the US)
37
What are “end-of-pipe-solutions”
Methods used to remove already formed containment from a stream of air, water, waste, product or something similar. Called end of pipe because they are implemented as a last stage before the stream is disposed or or delivered.
38
U.S. Pollution prevention Act 1990?
Green chemistry’s origin, became a formal focus and a new direction of the EPA
39
What are the three aims of green chemistry?
Reduce toxic waste Reduce toxic consumption of resources and ideally se renewable resources Reduce energy consumption
40
What is green chemistry?
The design of chemical producers and processes to reduce or eliminate the use and generation of hazardous substances Encourages companies to voluntarily find ways to reduce environmental consequences of their activities
41
What are the 12 principles of green chemistry ?
1. waste prevention 2. designing safer chemicals 3. less hazardous chemical synthesis 4. using safer solvents 5. minimize the risk of accidents 6. catalysis >>> stoichiometric reagents 7. real-time analysis for pollution prevention 8. design for energy efficiency 9. using renewable feedstocks 10. design for degradation 11. atom efficiency 12. reduce derivatives
42
What are the presidential green chemistry challenge award categories?
Founded in 1996 by EPA 1. Alternative synthetic pathways (less toxic) 2. Alternative reaction conditions (solvents with reduced impact on human health) 3. Design of safer chemicals (less toxic and safer) (like hairpin technology)
43
What is harpin technology?
Non toxic, neutrally occurring, biodegradable portions as n alternative to traditional pesticides Highly effective alternative to crop production that leads to greater crop yield and quality
44
What is atom economy
-Assesses the efficiently of a reaction -%atom economy = molecular mass of atom used / molecular mass of all reactants x100 -What atoms of the reactants are incorporated into the final product and which are wasted?
45
How was Ibuprofen made more sustainable ?
Started with 40% atom economy. (60% waste) 1997 - redesigned in three steps: 1. Acetic acid (a by product from the acetic anhydride) is isolated and utilized 2. Auxiliary materials are eliminated (solvents, AlCl promoter) (Lowered the consumption of reactants and auxiliary substances while simutainiously reducing waste) Atom economy is now 77%
46
How was polystyrene made more sustainable?
It is a common polymer that is sued to make everyday items 10 million tons produced per year Made from CFC’s or low molecular weight hydrocarbons (“blowing”) agents Dow Chemical Midland/MI looked for alternatives where CO2 can be used 100% as the blowing agent. Now the material remains flexible for a longer time PGC award 1996
47
supercritical and liquid carbon dioxide before green chemistry
CO2 can be liquified by pressure (attractive due to low viscosity, low polarity, and wetting ability) Supercritical CO2 can be sued as a solvent in the electronic industry CO2 dissolves small organic molecules, but larger molecules are insoluable. To increase solubility in water, surfactants (soap, detergents) are added. This means that polar solvents can dissolve less polar materials such as oil and grease
48
Supercritical and liquid CO2 post green chemistry
Joseph desimone (1997) Developed polymeric surfactants where… CO2 Phillic regions interact with CO2 Co2 phobic regions interact with each other So now substances that normally didn’t dissolve, dissolve in the micelle He founded a dry cleaning chain high uses liquid CO2 and surfactants in stream of polychlorloethylene (used in VOC’s, is a carcinogen)
49
Main properties of water:
-dipolemoment — 1.84 D - high melting and boiling point -15 different crystal structures -105 degree angle -open crystal structure -polar (good solvent) -highest dielectric constant -high surface tension Transparent to visible and UV light -pH 7
50
Who was cavendish?
Discovered water is a compound make of O and H atoms 1781
51
Which is the most prevalent water structure?
Hexagonal ice, where you’d expect o—h - - - - - -o bonding
52
What is a dielectric constant? How does it relate to water?
Water has a high dielectric constant This indicates a solvents ability to filter charges
53
Why is water’s dissociation constant important?
It means the rate of the forward reaction = the rate of the reverse reaction and he concentration of the reactants and products don’t change at equilibrium
54
Why is the structure of water controversial?
Could be one of two things, A. A mixture of two or more species B. A continuous model
55
What is hydrogen bonding?
Form between neighbouring hydrogen and oxygen atoms of adjacent water molecules
56
Who was Pauling?
1938 — discovered hydrogen bonds
57
What is the heat capacity of water? Why is that important ?
44 J/mol at 25 degrees Highest among all common liquids Water absorbs and stores a lot if heat, which is why the land around a large body of water (such as the Great Lakes) is temperature stabilized
58
Why is ice’s crystalline structure important?
It’s open crystalline structure of ice is responsible for its low density compared to water Why ice floats, and organisms are bale to survive in the winter
59
What are the worlds estimated salt water sources?
Oceans - 97% Salt lakes - 0.008%
60
What are the worlds estimated fresh water sources?
Polar ice - 2% Ground water - 0.61% Lakes Soil humidy Atmospheric vapour Riveres
61
_____ of fresh water lies in polar ice caps and alpine glaciers _____ of fresh water lies in ground water _____ of fresh water lies in accessible surface water
79% 20% 1%
62
What are the highest concentrated ions in natural waters?
HCO- = 9.6 x 10^-4 ppm Ca 2+ = 2.8 x 10^-4 ppm NOTE: no Fe or Al because they form insoluable hydroxides
63
Water is key for ______. Such as the nitrogen, phosphorus, sulfur, mercuric cycles
Nutrient cycling
64
What are the Canadian drinking water guidelines?
The maximum acceptable concentration in mg/L (pH 6.5-8.5) in various substances: 1. Arsenic = 0.025 2. Cadmium = 0.005 3. Chromium = 0.05 (These are carcinogens)
65
What is Henry’s Law?
The amount of gas that can be dissolved in water Equal to the concentration of the dissolved species divide by the partial pressure of the gas: Ex.K = [Xaq] / Px [Xaq] = K x Px K = Henry’s law constant Px = partial pressure of a gas
66
What is the Lake Nyos Distaster?
August 21st 1986 at 7:30 Pm 240,00 tons of CO2 Lake Nyos was formed in a creator formed from volcanic origin. The base helped trapped gases that would seep upwards from underlying rock and magma An earthquake triggered a landslide in the lake which force this CO2 out of the water and into the city
67
What is the Clausius Clapeyron Equation/relation?
Specifies the temperature dependence of pressure at a phase trasnitition THE SOLUBILITY OF GASES IN WATER DECREASES WITH INCREASING TEMPERATURE
68
CO2 sources:
Air Release by microbial decay or organic matter
69
What is the CO2-bicarbonate-Carbonate system?
important buffer system Includes 8 reactions Gaseous CO2 waste + H2O —> H2CO3 H2CO3 —> H+ + HCO- The increase of H+ ions released increases pH
70
What is weathering?
Acids formed on the surface of the earth can effetivly attack/ dissolve rock minerals Requires the abiotic formation of acids Once formed abiotically, acids can react with minerals CaCO3 and MgSiO3 containing rocks are most suspectable to weathering
71
What creates the sea’s saltiness
The amount of dissolved inorganic minerals in the ocean Salinity :
72
What are the most common ions in sea water and some marine organisms?
Cl = 55% Na = 31% Sulfate = 8% Mg = 4% Organisms contain higher concentrations than water does
73
River vs ocean water
Ocean has more Ca2+, more Cl, more Mg2+ Because: volcanic eruptions produce Cl- Hydrothermal vents produces ca and mg
74
Why does salinity in the oceans not increase over time?
Salts are continually removed by processes such as deposition, evaporation, and sea spray
75
What is a global biogeochemcial cycle ?
Dynamic circulation of the elements between the Atmosphere Hydrosphere Bioshpere Geosphere Anthrosphere
76
How does soil effect GBCE cycles
Soil processss effect the amount of carbon, nitrogen, phosphorous, sulphur
77
What are Macro elements
Relatively abundant in the earths crust Most abundant: Oxygen Silicon Phosphorous —— eutrophication of lakes Carbon—— global warming Sulfur —— acid rain Nitrogen —— eutrophication of lakes
78
How are deep sea ecosystems affected by climate change?
Deep. Sea communities are coupled to surface production. Global change alters the function of ecosystems and the way the carbon is cycled in ecosystems
79
What are trace metals?
Not abundant in the earths crust (mercury and arsenic)
80
Why is the mercuric cycle important in GBCE cycles
Atmosphere transfers liquid mercury to remote land masses in long range transport Causes bio accumulation of mercury in food chains
81
How are phytoplankton related to GCBE cycles? Why are their populations limited?
Phytoplankton are responsible for about Hal;f of the photosynthetic fixation of carbon on earth Photosynthetic plankton are limited : - need C,N,P, Si and micronutrients (Fe and Zn) - iron fertilization should increase the growth and therefore sequester atmospheric CO2 by depositing carbon in the sediment
82
What is iron fertilization?
A potential technique for extracting some of the CO2 from the atmosphere and depositing in the ocean depths Artificially adding iron to deep sea oceans would cause a phytoplankton bloom, thereby locking carbon away in their photosynthetic activities. Does not have great potential for sequestering carbon however

Chem 321 (6 decks)

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