Geochemistry on the JR - long version

A fascinating look at geochemistry through the eyes of three prominent scientists in the field. Filmed aboard the JOIDES Resolution during Expedition 344: CRISP October - December, 2012.

[thatsjusthim]

I loved this mini documentary, captivating delivery of the message! I hope to see more like it in the future.

[Jfresh]

Please, can anyone help me?
Illustrate an organic contaminant (e.g. benzene) plume that is entering a previously uncontaminated aquifer from a point source (e.g. a leaking underground storage tank), and show the predominant terminal electron accepting processes that you would expect to be occurring at different regions of that contaminant plume. “Defend” this by determining the thermodynamic favorability of these different terminal electron accepting processes, assuming the potential terminal electron accepting processes would be aerobic respiration (O2reduction), Mn(IV) (pyrolusite) reduction(to Mn2+), Fe(III) (ferrihydrite) reduction(to Fe2+), sulfate reduction(so sulfide), and methanogenesis.Before calculating the energetic favorability of these processes, produce balanced reactions depicting these terminal electron accepting processes based on H2as the electron donor (be sure to normalize all reactions on the basis of one mole of H2). Explain how the thermodynamic favorability of the different terminal electron accepting processes.A table that includes ∆G0frelated to this question is provided at the end of the exam.Why might it be “scientifically defensible” to use H2 for these calculations, and not benzene.

Chemical Species include:
Mn(2+)
MnO2
H2
H(+)
H20
S(0)=elemental sulfur
HS(-)
SO4(2-)
Fe(OH)3
Fe(2+)
CO2
CH4
O2

∆G•f (correlates to the chemical species)
-228 kJ/mol
-457 kJ/mol
0KJ/Mol
-40kJ/mol (@ pH 7)
-237 kJ/mol
0
+12KJ/Mol
-744Kj/Mol
-692Kj/Mol
-83KJ/Mol
-397KJ/Mol
-34KJ/Mol
16.4KJ/Mol


Please, I know it is long, but if anyone can help with this, it would help me out a lot.