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methanol solution

Posted: Mon Jan 18, 2010 4:19 pm
by Skydude176
I'm doing a project with a methanol fuel cell. I need a solution of 3% methanol in distilled water in order to power the cell. I need help with two things:

1.) I need to find the amount of stored energy, in joules, of 3% methanol solution. Does anyone know how I can find this measurement?
2.) Does anyone know where I can buy this solution? I haven't been able to find it online.

Thanks!

Re: methanol solution

Posted: Mon Jan 18, 2010 5:25 pm
by kgudger
I'm not sure if "combustion" in a fuel cell is the same as combustion in air, but this site http://www.lngplants.com/Thermodynamics2.htm lists the following information about methanol:
For methyl alcohol one has
CH3OH + (3/2)O2 = CO2 + 2H20 + 183.0 kilocal/mole
You can find the moles in your solution from the weight. (This assumes that the solution is 3% by weight.) Subtract out the weight of the water, and what is left is the amount of methanol you have. The molar mass can be used as kg / mole. I found the value for methanol here: http://www.economicexpert.com/a/Methanol.htm and is 32.04 amu.

There are several sources (science supply stores) that carry (almost) pure methanol. You can make your own solution from the pure stuff - just remember that it is extremely poisonous and a skin irritant as well.

Keith