Chemical Forums
Chemistry Forums for Students => High School Chemistry Forum => Topic started by: 1z3 on April 01, 2016, 06:49:02 AM
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When doing past papers, I often lose marks in the equation balancing department. I've looked online/youtube to find a reliable way of balancing any equation and I'm always left disappointed.
The only reliable method I seem to know is simply trial and error but this often lets me down as reactions become more complicated.
For example, I've been trying for around 20-30mins now trying to balance the half cell reactions in a direct alkaline ethanol fuel cell:
I've worked out the oxidation and reduction reactions but I am stumped on how to balance them using a reliable logical process. I can look up the answer but I need to know how for the exam.
C2H5OH + OH- ----> CO2 + H2O + e-
O2 + H2O + e- -----> OH-
I know the overall is simply combustion of ethanol: C2H5OH + 3O2 ----> 2CO2 + 3H2O
If anyone could help, it would be greatly appreciated.
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http://chemwiki.ucdavis.edu/Core/Analytical_Chemistry/Electrochemistry/Redox_Chemistry/Balancing_Redox_reactions#Basic_Conditions
Be very careful about multiplication and addition and writing clearly. It's easy to mess up one little thing and then the whole process is thrown out of whack.