[boarboy]

Hello,
I am having trouble completing the two following questions for an environmental chemistry assignment.

2. Using balanced redox reactions, predict the COD of a sample of natural water containing 22ppm of ethanol and 46ppm of methanol.

I have calculated the two reactions to be:
2CH3OH + 3O2 --> 2CO2 + 4H2O
CH3CH2OH  + 3O2 --> 2CO2 + 3H2O 
Now I simply do not understand in anyway how to deal with COD.

Also.
3. In a waste to energy incineration plant, approximately 80% of municipal solid waste is combusted. The remainder is ash.
a. If we assume that the combustible fraction of MSW is primarily cellulose, with the empirical chemical formula CH2O and having a Hf = -212kj/mol, how much heat is released per tonne of MSW?’

This is the calculation I came up with, but seeing as all other calculations in this question deponds on this first value being correct I was wondering if anyone could confirm it? I am not completely sure if I have done it right because I feel as though I should use Hess law but if that is the case I do not know what calculations would follow after using Hess.

-212kj/mol x 1mol/30.026gCH20 x 1000000g/1 tonne = -7.06x106kj/tonne

thanks!
Jp

[Borek]

Calculate amount of oxygen required to oxidize both ethanols, it is a HS stochiometry.