Term
| The sun emits what UV range most? |
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Definition
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Term
| What ranges of UV have very harmful biological effects? |
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Definition
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Term
| The ozone layer screens out what percent of UV B |
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Definition
|
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Term
| Where is the ozone of the ozone layer created? |
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Definition
| In the atmosphere, not on earth's surface |
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Term
Photodissociation of O2
O2 --> O+O |
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Definition
| Reaction is strongly endothermic requiring an input of 495 kJ/mol or 4.77 eV, which is in the UV-C. There are not many photons in UV-C. |
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Term
| No UVC reaches the earth because of what molecule? |
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Definition
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Term
Photodissociation of O3
O3 --> O2+O |
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Definition
Endothermic
Requires 105 kJ/mol, which is less than O2 reaction. |
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Term
| At what UV range does o3 absorb most strongly? |
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Definition
|
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Term
| What biological effects does UVB have? |
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Definition
| sunburn and genetic disruption |
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Term
| Almost all of the UVA reaches the surface |
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Definition
| SHUT UP... I know this isn't a question.... BUT KNOW IT! |
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Term
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Definition
| There are factors that a reaction must overcome to go. For example if it is endothermic or has a reaction barrier. These factors determine the actual probability of the reaction once the encounter has taken place and this is what k is summarized as. |
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Term
| What is k proportional to if there is an energy barrier Esub b? |
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Definition
| exponent(-Esub b/kbT) when kb = universal Boltzmann constant. |
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Term
| What is the Dobson unit and why do we use it? |
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Definition
| The dobson unit is the thickness of the layer that the gas would form if it were all brought to a standard pressure and temperature at the surface of earth. The reason for the dobson unit is: ozone concentration varies by greatly by altitude and the total ozone in a column of unit area is more important than the concentration at any particular height. |
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Term
| There are three (variations) for break down ozone what is result of the first X + O3 --> |
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Definition
--> XO + O2
and,XO + O --> X+02 NET= O3+O > O2 |
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Term
| For this reaction, X + photon --> Y, at what rate does it proceed at? |
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Definition
R = k[X][v]
where v is the flux of photons of the proper wavelength through the region where the reaction happens. |
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Term
| There are three (variations) for break down ozone what is result of the first X + O3 --> |
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Definition
--> XO + O2 and, X'+O3-->X'O+O2
and, XO+X'O-->X+X'+O2 NET 2O3-->3O2 |
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Term
| What equations cause ozone levels to peak in the mid to low stratospheric levels? |
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Definition
the chain reaction of:
O2+UVC-->o+O
o2+0---> o3 |
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Term
| What is the single largest source of Cl in our atmosphere? |
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Definition
| CFC (chlorofluorocarbons) |
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Term
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Definition
|
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Term
| What is the most prevalent element in Ozone destruction and one reason why? |
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Definition
| Chlorine Cl, REACTIVE, needs one electron to fill outer shell |
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Term
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Definition
|
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Term
| What properties of CFCs are ideal? |
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Definition
| inert, nonflammable gas,boiling point near room temp. so it can be transported and stored as a liquid and used as a gas |
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Term
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Definition
|
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Term
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Definition
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Term
Chlorine Destruction equation GO:
Cl+O3 --> ?? |
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Definition
Cl+O3->ClO+O2 (twice)
ClO+ClO->Cl2O2, then Cl2O2 +UVC-> ClO2+Cl,
then, ClO2->O2+Cl, NET: 2O3 -> 3O2 |
|
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Term
| The break down of CFC-12 by UVc once it gets to stratosphere |
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Definition
|
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Term
| The break down of CFC-11 by UVC once it gets to the stratosphere |
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Definition
|
|
Term
| Two other main sources of Cl in the atmosphere |
|
Definition
Carbon tetrachloride- CCl4
Trichloroethane- C2H3Cl3 |
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Term
| What is dangerous about the release of the Cl molecule into the atmosphere? |
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Definition
| catalytic ozone destruction |
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Term
| What is another radical that is dangerous in the atmosphere that is released from some cleaners? |
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Definition
|
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Term
|
Definition
| Lethal dose that kills 50% of the population |
|
|
Term
Rank the strength of these bonds- Strongest to weakest
H-F
H-Cl
H-Br |
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Definition
|
|
Term
| What are the two main classes of Bromine containing compounds? |
|
Definition
Halons( compounds that contain bromine but no hydrogen- CF3Br)
methyl bromide |
|
|
Term
| On a lethal dose curve where are the threshold points? |
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Definition
|
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Term
| Why are HCFC's a better for the environment than CFC's? |
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Definition
| The C-H bond is more susceptible to chemical attack than the C-Cl bond, so these compounds are broken down already in the troposphere for the most part. Also it does not create HCl. They still do destroy ozone though. HFC's are the ideal replacement. |
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Term
| the ozone holes appear only near the... |
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Definition
|
|
Term
| What time of the year do we see the hole? |
|
Definition
| September (australia spring time) and is pretty much gone by december |
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Term
| Reactions that take place to get rid of Cl and ClO (elements/compounds that destroy ozone) |
|
Definition
Cl+ CH4--> HCl + CH3
ClO+NO2---> ClNO3 |
|
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Term
| what happens to the inactive forms of Cl? |
|
Definition
ClNO3+ H2O---> HOCl+HNO3
HCl--->H+Cl
Cl+HOCl---> Cl2+OH
Cl2---> is gas and escapes into the atmosphere and is decomposed by UV light and atomic chlorine catalyzes ozone destruction |
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Term
| What is significant about the north and south pole in the activation of Cl? |
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Definition
| Normally there is no weather in the stratosphere but in the north and south pole, polar stratospheric clouds (PSCs) will form in -80C. These ice clouds have a thin layer of water on them that can activate the Cl |
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Term
| What is significant about the north and south pole in the activation of Cl? |
|
Definition
| Normally there is no weather in the stratosphere but in the north and south pole, polar stratospheric clouds (PSCs) will form in -80C. These ice clouds have a thin layer of water on them that can activate the Cl |
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Term
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Definition
| AKA biomagnification. The fat-soluble molecules are eaten by organisms low on the food chain. They build up a certain low concentration. An organism high up in the food chain eats the lower one. It is not able to excrete this substance and therefore, as time goes on the toxin builds up. |
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Term
| What explains why the ozone hole starts in the spring and is not apparent in the winter |
|
Definition
| In the polar winter there is no sunlight (UV) to activate the Cl |
|
|
Term
| In which pole is the hole larger? |
|
Definition
|
|
Term
|
Definition
para dichloro diphenyl trichloroethane
it is persistent because:
low volatility (tendency of a substance to vaporize)
No bonds which can be broken by visible light.
chemical and biological stability (C-Cl bonds very strong)
Very low solubility in water (has no O atoms - not polar thus not soluble)(if it is not water soluble it can not be excreted)
highly toxic to insects.
It does biocencentrate. |
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Term
| Why is oil considered a finite resource? |
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Definition
| 100,000 yr time scale for the formation of oil and the 100-200 year time scale oh which we are using it. Also the price run up in the last few years |
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Term
| What do living organisms change DDT to? |
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Definition
| DDE, which = DDT minus and H a Cl. |
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Term
| When we look at how much oil is on left on earth we are talking about light sweet crude oil... what does this mean? |
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Definition
| It can be pumped from the ground and does not contain much sulfur |
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Term
| How did Hubbert predict the peak of oil production would be in 1970? |
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Definition
| made assumption that the amount produced in a given year divided by the cumulative amount produced up until that year would be proportional to the amount left in the ground |
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Term
| Production rate/amount already produced= K x (amount left) |
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Definition
| K is a proportionality constant and total just refers to the total amount in the ground.(about oil in ground) |
|
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Term
| What is the problem with oil from tar sands? |
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Definition
| The oil is bonded to sand and must be removed by mixing the sand with very hot water and NaOH- need large amounts of water and energy |
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Term
| Look into the linear and bell graph relationship of oil production- lecture 41- do not know how to put into notecards... sorry my loves! |
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Definition
|
|
Term
| Natural radioactive elements |
|
Definition
The series with 92U238 and continues all the way to Pb206. In all reaction chains it begins with a long-lived radioactive species and ends with a stable ones.
See lecture 37 for graph. |
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Term
|
Definition
The neutron is absorbed by the 92U235 whcih converts to the highly unstable 92U236, which spontaneously splits into two smaller pieces. An example:
92U235 + 1n0 → 92U236 → 35Br89 + 57La144 + 3 1n0, |
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Term
| What is the form most natural radioactivity we are exposed to is? |
|
Definition
|
|
Term
| What is more raidoactive? Us or our surroundings? |
|
Definition
| Humans due to the radioactive K in our bodies. |
|
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Term
| What is the fate of the alpha particle? |
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Definition
| they are charged so they bang into electrons in the atoms on their path (ionize).The more dense the material the quicker the alpha particle comes to a stop because it transfers energy to the electrons until it has none |
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Term
| fate of the beta particle |
|
Definition
| lighter and travel in a less straight path. smaller charge so it can go further |
|
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Term
|
Definition
| not charged so much more penetrating. can ionize atoms |
|
|
Term
| what is background radiation |
|
Definition
| gamma ray and internal emissions. we are not close enough to external pure alpha and beta sources to get radioactivity from them |
|
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Term
| what does a curie measure |
|
Definition
| strength of a radioactive source |
|
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Term
|
Definition
| the dosage of ionizing radiation |
|
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Term
|
Definition
| used for biological applications and is the dosage of ionizing radiation measured in different biological densities |
|
|
Term
| What is characteristic of the nuclear fission fragments that break up after the primary reactions? |
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Definition
| They are two large fragments of unequal weight caused by reactions of heavy nuclei. |
|
|
Term
| What is the natural dosage of radiation per year? |
|
Definition
100 millirads/year
30%-cosmic rays
50%-gamma emitted from materials in the enviro
20%- internal emissions |
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Term
|
Definition
| Neutrons appear on both sides but after the reaction there are more neutrons than before, which can initiate more reactions producing a chain reactions. Each step releases energy. |
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Term
| What is the fuel for nuclear reactors? |
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Definition
| 92U235. The problem is that natural uranium is 99.3% 92U238 and .7% 92U235. This needs to be enriched by separation to 3-5%. |
|
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Term
|
Definition
H20-->H2O^+ + e^-
H2O^+--> H^+ + OH*
OH* + OH*---> H2O2
H2O2---> undesirable |
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|
Term
| What does the moderator do in nuclear reactions? |
|
Definition
| it slows down the neutrons so a chain reaction can be achieved. Graphite (carbon) or water is often used |
|
|
Term
| Nuclear reactors common parts |
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Definition
| a core containing the nuclear fuel, moderator, control rods and coolant. |
|
|
Term
| what cells are damaged by radiation |
|
Definition
|
|
Term
| what is the LD50 in rads of radiation |
|
Definition
|
|
Term
| explain the threshold model of radiation |
|
Definition
| At small amounts it does not cause cancer because we have a natural defense against it. (we have mechanisms for repairing damaged DNA) |
|
|
Term
| explain the linear model of radiation |
|
Definition
| the amount of genetic material damaged is proportional to the dose and the chance of cancer is in turn proportional to the genetic damage |
|
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Term
| Types of Nuclear reactors |
|
Definition
Boiling water reactor. Water acts as bot a coolant and a moderator in the core. This water runs through the turbine and back to the core.
Pressurized water reactors (most common) - which differ from boiling water reactors only in that the primary coolant, water, does not boil and does not get to the turbines. As a safety precaution they both will stop moderation and radiation if the coolant is lost.
Fission reactor - the fission reactions can take many different paths. |
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Term
|
Definition
|
|
Term
|
Definition
|
|
Term
|
Definition
|
|
Term
|
Definition
| started by a valve sticking in the condenser, which prevented the flow of coolant water to the core. |
|
|
Term
|
Definition
| same number of protons but different number of neutrons |
|
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Term
|
Definition
| Emergency power was shut off and the temperature of the water was turned down. Usually it is hard to restart due to the buildup of Xe135 but the operators restarted it anyway. |
|
|
Term
| What is the most stable nucleus |
|
Definition
| 26Fe56- highest binding energy per nucleon |
|
|
Term
| what do elements higher than Fe56 tend to do? |
|
Definition
| Split up because they are unstable and lighter nuclei tend to fuse together |
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Term
| Why are there no elements heavier than uranium on earth? |
|
Definition
| Nuclei decay at varying rates and decay faster as the atomic number increases. when the atomic number is greater than uranium (92), the rates are fast compared to the age of the earth so there are no elements heavier than this |
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Term
| When is a element thought of as radioactive |
|
Definition
| if the half life is shorter than 10^10 years |
|
|
Term
| an example of alpha decay |
|
Definition
| 90Th232---> 88Ra228 + 2He4 |
|
|
Term
| Calculation efficiency factor (EFF) |
|
Definition
P = EFF x C x A
area = A
Power = P
solar constant = C |
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|
Term
|
Definition
|
|
Term
| What do solar cells use to conduct electricity? |
|
Definition
| semiconductors, which is a material that is an insulator in its pristine state. To make electricity you need to coax the free electrons generated into an external circut before they recombine. |
|
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Term
|
Definition
| Use the concept of p-n junction. Difference is that instead of semi-conductors, silicon is being used. So basically it is p-n because electrons create holes once they are absorbed and these holes are swept to the electrodes. |
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Term
|
Definition
| Expensive and only a fraction of the solar constant is absorbed. Costs about $.30/kW-hr. This is due to the high cost of Si. |
|
|
Term
| when a nucleus decays,what does almost all the energy appear as? |
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Definition
| kinetic energy of the lighter fragment |
|
|
Term
| there is usually a gamma ray with alpha and beta decay |
|
Definition
|
|
Term
Basic Fusion Energy reaction
or D-T reaction
D is heavy hydrogen and T is tritium. |
|
Definition
2H+ 3H --> 4He (3.5 MeV) + n (14.1 MeV)
This reaction is very potent because of the extreme stability of the He nucleus. |
|
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Term
| Positives and Negatives of fusion |
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Definition
| not radioactive so not dangerous. Also, D is plentiful, but you need to accelerated toward one another. Or at a very high temperature. T must be manufactured. |
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|
Term
| What are the human bodies defensive mechanisms to toxins? |
|
Definition
| Excretion, through kidneys, lungs, liver (water soluble only) AND Metabolism (fat soluble toxins are processed |
|
|
Term
| What was a remedy for treating toxins developed by Britains? |
|
Definition
| British Anti-Lewisite (bonds to metallic toxins) and makes them water soluble so they body can process them |
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|
Term
| What equation determines bioaccumulation of toxins? (think Homework) |
|
Definition
| C= Csub(s)*(1-e^-k*t) where C= final conc, Csub(s)=intake/elimination efficiency, k is elim eff., t is time |
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|
Term
| What are organochlorines and what do they consist of? |
|
Definition
| Used in pesticides/herbicides they consist of: benzene rings and chlorine therefore they persist in the environment |
|
|
Term
| Name some common organophosphates (Same as organochlorines but with PO group) also are used as pesticides. |
|
Definition
| Dichlorvos(LD50= 25mg/kg) Parathion(LD50 =3mg/kg) Malathion(880mg/kg) These mess with the nervous system of insects |
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|
Term
| Name two choloracetamides. (mixture of the two was made popular in Vietnam) |
|
Definition
| Agent Orange: consisted of common weed killers dichlorophenoxyacetic acid and trichloro... same as prior (remember structure from homework |
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|
Term
| Why is tetrodotoxin (natural,puffer fish toxin) so harmful? |
|
Definition
| LD50=mg It binds to Sodium(Na) channels in nerve cells causes paralysis |
|
|
Term
| Important! Discuss ciguatoxin (prof Joynt's toxin) |
|
Definition
| Produced by algae and bioaccumulates in fish, people eat fish and get sick. Affects sensory nerve conduction, can take years to get rid of. |
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|
Term
| What are PCBs and why are they harmful to environment? |
|
Definition
| Phenyl rings with Cl subsituted for H. Used in insulators and dumped into envir. Persist b/c of Cl, sit in riverbeds and are fat soluble, can bioaccumulate |
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|
Term
| What are the 3 important toxic actions of metals? |
|
Definition
| 1. Inhibit enzymes 2.Subsitute Chelated ion (prevent hemoglobin for transporting oxygen) 3.Disrupts nerve conduction |
|
|
Term
| Why is CH3Hg (methyl mercury) such a harmful molecule? |
|
Definition
| Bioaccumulates, affects child development, Low LD50, sensory impairment(paresthesia), ataxia(muscle control), dysarthria(slurred speech) |
|
|
Term
| Why is lead such a bad naturally occurring toxin? |
|
Definition
| In drinking water, gases, can get into body and cause gastrointestinal/nerve problems, anemia, BIGGEST effect on development of children (dumber kids) |
|
|
Term
| What are common units of energy we used in class? |
|
Definition
| eV electron volt (chemistry), MeV(10^6eV)nuclear scale, Joule(human level, 1food cal=1000 scientific cal=4.184*10^3Joules, Btu(British thermal unit 1=1055J, 1Kw/hr=3.6*10^6J, National QuadBtu=10^15Btu |
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|
Term
| How many gallons in a barrel of oil? Btu's in 1 ton of coal? |
|
Definition
| 42, 2.66*10^7Btu ~roughly 4 barrels of oil |
|
|
Term
| What is the largest source of energy production in US? What is greatest sourced consumed (i.e. what do we import)? |
|
Definition
|
|
Term
| What is total US energy use, per person? |
|
Definition
100 QuadBtu's=1.055*10^20J/yr
1.055*10^20J/3*10^7s= 3*10^12W in power, so each person uses about 10000W/yr |
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|
Term
| How does a power plant work? |
|
Definition
| Fuel is burned, heats water, creates steam that goes through turbines, and turns electrical coils in a magnetic field in a generator that creates electricity Specifically 1.Compression of water 2.Boiling 3.Expansion of Steam 4.Condensing (steam cools back to cold water) |
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|
Term
| How does a power plant work? |
|
Definition
| Fuel is burned, heats water, creates steam that goes through turbines, and turns electrical coils in a magnetic field in a generator that creates electricity |
|
|
Term
| Where does heat come from in a combustion reaction? |
|
Definition
CH4+2O2->CO2+H2O+HEAT
1kg of methane produces 55MJ of heat energy |
|
|
Term
| What is the equation for EFF? |
|
Definition
| Efficiency= Work given out-work put in)/Heat so, EFF= 1-T(envr)/T(combustion) T(envr) = 285K Modern powerplants=0.4 EFF |
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|
Term
| How do you measure Power out of a plant? |
|
Definition
P(out)=EFFactual*H*R (R=fuel consumed) (H=heat of combustion per kg H)
example: 200MW/(.4*55MJ)=8.3kg/s*3600=
29,880kg of CH4 per hour |
|
|
Term
| How do you solve global warming? |
|
Definition
| Stabilization wedges(Small Changes) don't be "Business as usual." Wedge categories include: Efficiency/Conservation, Fuel Shifts, and Carbon Sinks (forest management) ASK MATT if u want more detail :D |
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|
Term
| there is usually a gamma ray with alpha and beta decay |
|
Definition
|
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