Hi there: I'm trying to balance a reaction in which methane is oxidized by citric acid in solution. Both methane and citric acid will be transformed into carbon dioxide. To begin, I checked that the reaction is indeed a redox reaction. C6H8O7→CO2 So, I calculated the oxidation number for carbon goes from +6 to +4. A reduction. CH4→CO2 I calculated the oxidation number for carbon goes from -4 to +4. An oxidation. This seems reasonable so far. Then, I balanced my half-reactions. C6H8O7+5H2O→6CO2+18H++18e- CH4+2H2O→CO2+8H++8e- Now comes the part that has me baffled. How do I combine these half-reactions and not end up with loads of electrons since they are on the right hand side of both half-reactions?! Clearly, I've done something very wrong. Any help would be appreciated.