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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
Q

Particulate matter has a ______ effect on humans than pollutant gases

A

Greater

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26
Q

What is PM10

A

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

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27
Q

What is PM2.5?

A

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

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28
Q

Why are larger particles of less health concern to humans?

A

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

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29
Q

How does engine exhaust relate to PM 2.5

A

Exhaust from diesel engines has been classified as likely to be a carcinogenic to humans

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30
Q

___% increase in a city’s mortality rate for every ___ increase in the PM 2.5 index

A

3%

5ug/m^3

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31
Q

What are the USA environmental distorts in the 60s and 70’s

A

62 — Rachel Carson published silent spring about DDT (insecticide

69 — cayahoga river in Cleveland Ohio caught on fire

Mid 70s — the love canal

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32
Q

What is the EPA?

A

US. Environmental protection agency, founded in 1970

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33
Q

What are the pollution control programs?

A

Clean Air (1970) and Water (1972) Acts
Compensation and liability act (superfund act
“End-of-pipe-solutions”
US pollution prevention act (1990)

34
Q

What are the Clean Air and Water Acts ?

A

Attempt to control the release of toxic and harmful chemicals into the environment

35
Q

What is the love canal neighbourhood?

A

‣ 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
Q

What is the compensation and liability act?

A

The superfund act set up procedures and fund for cleaning up toxic waste sites (of which there are over 1000 in the US)

37
Q

What are “end-of-pipe-solutions”

A

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
Q

U.S. Pollution prevention Act 1990?

A

Green chemistry’s origin, became a formal focus and a new direction of the EPA

39
Q

What are the three aims of green chemistry?

A

Reduce toxic waste
Reduce toxic consumption of resources and ideally se renewable resources
Reduce energy consumption

40
Q

What is green chemistry?

A

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
Q

What are the 12 principles of green chemistry ?

A
  1. waste prevention
  2. designing safer chemicals
  3. less hazardous chemical synthesis
  4. using safer solvents
  5. minimize the risk of accidents
  6. catalysis&raquo_space;> 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
Q

What are the presidential green chemistry challenge award categories?

A

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
Q

What is harpin technology?

A

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
Q

What is atom economy

A

-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
Q

How was Ibuprofen made more sustainable ?

A

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
Q

How was polystyrene made more sustainable?

A

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
Q

supercritical and liquid carbon dioxide before green chemistry

A

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
Q

Supercritical and liquid CO2 post green chemistry

A

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
Q

Main properties of water:

A

-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
Q

Who was cavendish?

A

Discovered water is a compound make of O and H atoms
1781

51
Q

Which is the most prevalent water structure?

A

Hexagonal ice, where you’d expect o—h - - - - - -o bonding

52
Q

What is a dielectric constant? How does it relate to water?

A

Water has a high dielectric constant
This indicates a solvents ability to filter charges

53
Q

Why is water’s dissociation constant important?

A

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
Q

Why is the structure of water controversial?

A

Could be one of two things,
A. A mixture of two or more species
B. A continuous model

55
Q

What is hydrogen bonding?

A

Form between neighbouring hydrogen and oxygen atoms of adjacent water molecules

56
Q

Who was Pauling?

A

1938 — discovered hydrogen bonds

57
Q

What is the heat capacity of water? Why is that important ?

A

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
Q

Why is ice’s crystalline structure important?

A

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
Q

What are the worlds estimated salt water sources?

A

Oceans - 97%
Salt lakes - 0.008%

60
Q

What are the worlds estimated fresh water sources?

A

Polar ice - 2%
Ground water - 0.61%
Lakes
Soil humidy
Atmospheric vapour
Riveres

61
Q

_____ 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

A

79%
20%
1%

62
Q

What are the highest concentrated ions in natural waters?

A

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
Q

Water is key for ______. Such as the nitrogen, phosphorus, sulfur, mercuric cycles

A

Nutrient cycling

64
Q

What are the Canadian drinking water guidelines?

A

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
Q

What is Henry’s Law?

A

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
Q

What is the Lake Nyos Distaster?

A

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
Q

What is the Clausius Clapeyron Equation/relation?

A

Specifies the temperature dependence of pressure at a phase trasnitition

THE SOLUBILITY OF GASES IN WATER DECREASES WITH INCREASING TEMPERATURE

68
Q

CO2 sources:

A

Air
Release by microbial decay or organic matter

69
Q

What is the CO2-bicarbonate-Carbonate system?

A

important buffer system
Includes 8 reactions

Gaseous CO2 waste + H2O —> H2CO3
H2CO3 —> H+ + HCO-

The increase of H+ ions released increases pH

70
Q

What is weathering?

A

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
Q

What creates the sea’s saltiness

A

The amount of dissolved inorganic minerals in the ocean
Salinity
:

72
Q

What are the most common ions in sea water and some marine organisms?

A

Cl = 55%
Na = 31%
Sulfate = 8%
Mg = 4%

Organisms contain higher concentrations than water does

73
Q

River vs ocean water

A

Ocean has more Ca2+, more Cl, more Mg2+

Because:
volcanic eruptions produce Cl-
Hydrothermal vents produces ca and mg

74
Q

Why does salinity in the oceans not increase over time?

A

Salts are continually removed by processes such as deposition, evaporation, and sea spray

75
Q

What is a global biogeochemcial cycle ?

A

Dynamic circulation of the elements between the
Atmosphere
Hydrosphere
Bioshpere
Geosphere
Anthrosphere

76
Q

How does soil effect GBCE cycles

A

Soil processss effect the amount of carbon, nitrogen, phosphorous, sulphur

77
Q

What are Macro elements

A

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
Q

How are deep sea ecosystems affected by climate change?

A

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
Q

What are trace metals?

A

Not abundant in the earths crust (mercury and arsenic)

80
Q

Why is the mercuric cycle important in GBCE cycles

A

Atmosphere transfers liquid mercury to remote land masses in long range transport
Causes bio accumulation of mercury in food chains

81
Q

How are phytoplankton related to GCBE cycles?
Why are their populations limited?

A

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
Q

What is iron fertilization?

A

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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