Chemistry 310 – March 19 , 2013 – Tuesday
CO2 – Climate
Fossil Fuels – Energy
“Organics” – Toxic, Natural
Read the text book
1. >> Anthropogenic, Toxic, Natural Organics
2. Soild water atmosphere
3. Imagine that you are having an industrial spill. Solids gets poured and they go somewhere
4. We have the top soil level and below that we have a water table. This is the level to which fresh
water rises. Most of the fresh water in the world is not in the surface of the earth, not in lakes,
they are down below the soil. Down soil we get not sacrated water.
5. Below that we have bed rock.
6. In a natural industrial leakage. There are different types of spils. Tricholo ethelene – TCE
7. PCE- Perchloro ethelene – these are potential carcinogens and nasty . They have Chlorine in
them which makes them heavier than water. Density is >1 8. BTEX – Benzene Toluene Xylene – aromatic components of gasoline. Suspected carcinogen..
Aromatics are less denser than water.
9. Industrial spill stuff seeps down through the soil and the water table is saturated with
water the chlorinated material goes and hits the bed rock and pools at the bottom -> BTEX is
water but is not soluble in water they are aromatics so they pool up at the top of the water.
10. So now we have got the spills. Where do these compounds go to?
11. There are no of things which determines it
a. Ome of them are going to be on the surface and If they are really volatile they are going
b. if its not volatile and if its like a PCB or something big, it is going to go down. Soil is a
mixture of organic and inorganic mater. So it has a strong affinity for soils. So they are
going to be stuck in the surface of the soil for a long long time.
ii. Affinity to soil
iii. Organic solubility - Affinity to organic material – plans and organisms in the soil,
these are organic soluble and not water soluble, they are going to head off into
the biosphere very rapidly. They are going to get attached to the organic part of
the soil. Benezene abd trichloro ethane is not highly interactive,but something
big like DDT, BBT they interact with soil.
iv. Water solubility- if the material goes and hits off the water layer, the q is what
its water solubility is. Some of the heavily industrially polluted places you can
see oxins seeping out of the soil. High water solubility they will wash away
sooner, low water solubility : they will stay for long time.
v. Reactivity – which can occur anywhere. It can occur in the gas phase, aqueous
phase, can occur with microbes in the soil.
12. Partitioning: how do different organic chemicals partition in the environment. Trying to
understand from the molecular level what is going to govern the water pressure, vapor pressure
13. SLIDe: There is an incredibly wide variety of vapor persure. These are classic pollutants like
benzene, small halogeneated compunds, PCB’s PAH’s, aliphatic hydrocarbons like gasoline,
crude oil etc.
14. Vapor pressure changes from 10^-12 to 1atm others. Within this range you can see compounds
which are highly volatile.
15. Putting PCB and methanol into the enviroenmtn will never ever go nasty or into the
atmopshere, they are completely going to be in the soil with biologically mediated processes
16. Slide 2: water solubility: similar ranege, anywhere form above I molar unit, all the way upto
17. Vapor pressure
a. Definition: it will take a closed vesicle with a liquid.at high equilibirium you will reach a
steady state with the molecules in the gas pahse and liquid pahse. b. Then we have an equilibrium of liquid with gas and liquid.
c. We can weite and equibliruim constant for that, see below.
e. Liq Gas
f. Keq VP
g. DeltaG = -RTlnK eq
o 0 0
h. VP(T) = K (eq = exp(=DeltaG /RT) = Exp (-Delta H /RT) exp (deltaS /R)
i. If can’t understand listen to lecture recording: march 19 22 minutes.
18. Vapor pressure of the liquid is related to the entropy of vaporization. The magnitude is guided
by the enthalpy forces and entropy changes.
19. Molecular interactions that govern Vapor Pressure (Delta H 0VP)
a. Size – the larger the molecule the more energy is put into it to put it into a gas phase.
Smaller molecules are going to be more volatile thatn bigger ones.
b. Beside size other interactions affects the VP.
c. If there is an intermolecular forces you have liquid or solid, because if there is no
interactions you have gas.
d. Vanderwaal’s Forces ( 1 2kJ/mole) – very very small forces rising from momentarily
changes between molecules. Weak forces.
i. Dipole Dipole (Dipole – Induced Dipole) (5 10kj/mol)stronger than
vanderwaal’s. – the intera