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63 Cards in this Set
- Front
- Back
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what are primary and secondary particles?
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primary - are emitted directly into the atmosphere
secondary - formed in the atmosphere from gaseous precursors |
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_____'s Law says that a particle half the size of another particle will fall 4 times more slowly; so how are very small particles removed from the air?
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Stoke
raindrops |
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The most important property of particles is their what?
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diameter
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How are particles classified based on their size?
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Coarse: >2.5 micrometers
Fine: <2.5 micrometers |
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what is a tropospheric aerosol?
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collection of particulates (solid or liquid) dispersed in the air that have negligible fall speeds and are <100micrometers in diameter
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coarse particles originate from (natural/anthropogenic) sources and are mostly (primary/secondary)
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natural
primary |
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4 examples of coarse particles
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sea spray particles
soil dust debris from natural fires pollen & leaf litter particles |
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fine particles are formed mainly by ……………………between gases and coagulation of smaller species
(molecules) and are mostly (primary/secondary) |
chemical reactions
secondary |
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4 sources of primary fine particles?
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tires
vehicle brakes metal smelting vehicle exhaust |
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much sulfur in air is from dimethyl sulfide emitted from ____. This compound is oxides to ____ in the troposphere, then oxidized to ____ is the stratosphere creating a _____ ______ layer.
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much sulfur in air is from dimethyl sulfide emitted from OCEANS. This compound is oxidized to SO2 in the troposphere, then oxidized to H2SO4 is the stratosphere creating a STRATOSPHERIC SULFUR layer.
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3 sources of NH3
what impact does this have on acid rain? |
biological decay
livestock use of fertilizers this is the reason why rain over central US is not acidic! |
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why are particles of 0.01 micrometers of particular importance?
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they are Aitken nuclei, which are the nuclei that form clouds -> they affect the chemistry of atmosphere cloud formation
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what is the PM index?
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measure of the amount of Particulate Matter: micrograms per meter cubed
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PM10 is reported in many countries as the amount of inhalable particles, and averages 20-30 in urban settings. What does it mean?
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the amount (20-30 micrograms) per meter cubed of particles that are LESS THAN 10 micrometers
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Why is PM2.5 dangerous?
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Under than 2.5 micrometers particles are RESPIRABLE and can penetrate deeper into lungs
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the air pollution parameter that most strongly correlates to rates of disease/death is ...
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PM2.5
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3 reasons why large particles are less of a concern to health?
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1. they settle faster, reducing exposure
2. more efficiently filtered by nose and throat 3. have a smaller SA than smaller particles |
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diesel exhaust is likely to be what?
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carcinogenic
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green chemistry emphasizes what part of the consumer goods cycle?
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manufacturing
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3 events that triggered environmental reform in the US
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1. 1962 Rachel Carson's "Silent Spring" about DDT
2. 1969 Cayahoga River caught fire! 3. mid 1970's "Love Canal Neighbourhood" was built on a chemical dump - cost $400mil |
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what 2 acts were passed that attempted to control release of toxic/harmful chemicals into environment?
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clean air act
clean water act |
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what act set up procedure and provided funds for cleaning up toxic waste sites?
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Superfund act
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what are end-of-the-pipe solutions? do they work?
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aim to control risk by preventing exposure
hells no |
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supercritical CO2 (CO2 + pressure = liquid CO2) serves what 2 green chemistry purposes?
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1. acts as a solvent instead of other organic solvents (has low viscosity, low polarity, good wetting ability)
2. can replace perchloroethylene in dry cleaning |
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H atom attracted by 2 atoms instead of 1 -> _____ ______
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hydrogen bonding
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the polarity of water makes it's very able to _____ ions, which makes it a good ____
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hydrate
solvent |
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what feature of ice is responsible for its low density?
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open crystal structure
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water is at its highest density at what temp?
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4 degrees
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water has a heat of ______ that is highest among all liquids. What does this mean for environments with water?
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evaporation
temperature stabilization in areas adjacent to large bodies of water |
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water has the highest _____ constant of any liquid, which makes water ... for what purpose?
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dialectic
an excellent solvent to mediate biochemical processes and transport of nutrients/waste products |
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why is it important that water has a high surface tension?
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important in physiology, governs drop and surface phenomena on biomembranes
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what character of water allows PS to occur at considerable depths?
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transparent to visible and UV light
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why is it important that water has a high heat capacity?
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temperature stabilization of organisms and geographical regions
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what is the dissociation constant of water?
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H2O + H2O <-> H3O+ + OH-
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the structure of liquid water is controversial; what 2 theories are there about this?
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1. water is a mixture of two or more species
2. water is described by a continuous model |
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what are the 5 compartments of the hydrological cycle?
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clouds
oceans lakes+rivers ice ground water |
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hydrological cycle is driven by ___
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the sun
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what proportion of fresh water is frozen, in ground water, and is accessible surface water?
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frozen: 79%
ground: 20% accessible: 1% |
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Henry's Law: at constant temp the _______ of a gas in a liquid is proportional to the ______ ______ of the gas in contact with the liquid
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solubility
partial pressure |
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Henry's law: what are the variables?
[X(aq)] = K * Px |
X(aq) = concentration of gas in the liquid
K = Henry's law constant (depends on gas) Px = partial pressure of gas in atm |
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Lake Nyos: 1700 people died from CO2 poisoning after 240,000t were spewed into the atmosphere - what happened?
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vents were seeping CO2 at the bottom of the lake + cold rain -> dense surface water sank, causing complete overturn of the lake -> bottom waters forced upwards
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how does gas solubility in a liquid change with temp?
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solubility decreases with increasing temp (cold water has more gas)
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how can pollutants in a water body indirectly kill fish?
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degradation of org matter -> uses oxygen -> CO2 + H2O -> oxygen deficiency
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on what side of this equation is equilibrium? what does this mean (2)?
CO2 + H2O <-> H2CO3 <-> H+ + HCO3- |
left side
-meaning that most CO2 in water is not actually H2CO3 -and explains why pure water, equilibrated with unpolluted atmosphere, is slightly acidic |
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at different pH's water contains different proportions of CO2, HCO3-. and CO32- ... at what pH values do the dominant species change/?
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pH = 6.35 -> [CO2]=[HCO3-]
pH = 10.33 -> [HCO3-]=[CO32-] |
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CO2~HCO3-~CO32- are important because ...
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they act as a buffer system of water bodies
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what is the maximum pH that is sufficient to allow enough CO2 to be dissolved to be used for PS?
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need pH of 7 or lower
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what is alkalinity?
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measure of the ability of a water body to neutralize acidity
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what is the most abundant ion in lakes/rivers?
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HCO3-
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dissolution of rocks depends on ...
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the equilibrium between the speeds solubilization and precipitation
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what causes weathering?
2 examples |
abiotic formation of acids that can dissolve rocks/minerals
2 examples of abiotic formation: CO2 + H2O -> H2CO3- sulfuric acid |
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what are the 3 main contributers to the sea's saltiness (ie. amount of inorganic minerals dissolved)
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1. dissolution/weathering of rocks/minerals
2. volcanic activity 3. hydrothermal vents |
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salinity and pH of the ocean does vary, but what aspect does not change?
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the chemical composition
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what is responsible for the Cl- in the ocean?
the Ca2+ and Mg2+? |
Cl- = volcanic eruptions
Ca2+ and Mg2+ = deep sea vents |
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what are 3 sinks for salts in the ocean, explaining why they don't build up over time?
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deposition on sea floor
evaporation sea spray |
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global biogeochemical element cycles refer to the interchange of matter among these compartments (5)
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atmosphere
hydrosphere geosphere biosphere anthrosphere |
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what GBCE cycles should be studied?
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those that influence climate, fresh water and human health
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fluxes are measured in ...
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change in mass per unit time
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2 categories elements in GBCE cycles are studied ...
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1. macro elements (N, S, etc)
2. trace metals (Pb, Hg, etc.) |
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what is the 3rd major threat to our planet after biodiversity loss and climate change?
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nitrogen pollution
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3 steps to understanding a GBCE cycle
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1. identify species in a compartment (ie. -sphere)
2. establish biotransformations between species (ex. NH3 -> NO3) 3. determine which species can move between compartments |
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what effect "should" iron fertilization have on CO2?
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iron should increase phytoplankton growth, therefore sequester CO2 by depositing C into the sediments
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how can changes over time in the GBCE cycles be detected?
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by analyzing samples that contain chronological info about element concentrations. such as ice cores
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