Chemistry HELP! Redox Reaction :|

Its been a long while since i did these, but how do u do them agian? I remember something like finding the difference in charge between the 2 sides after balancing the equation. THen balancing the charge using H+ ions. THen use water to balance the H+ ions. Then finally add O2 to balance the O2 atoms. Was it something like that?

wait, now i remember, you have to seperate out the equation into the two parts. So MnO4 2- MnO2. First you balance out there oxygens using H2O So MnO4 2- MnO2 + 2H2O Then u add H+ to the other side of H2O to balance out hydrogen so: MnO4 2- + 4 H+ MnO2 + 2H20 Then u balance electron to make both sides equal, so u need to add 2 electrons to right hand side so: MnO4 2- + 4 H+ + 2 electons MnO2 + 2H2O (this is the first equation) Then for MnO4 2- MnO4 - you need to just add an electron to rhs (right hand side) to balance so: MnO4 2- MnO4- + e- Then you just balance electrons, so u need to double the second equation to make it 2 e- to balance the 2e- in the first equation. Making it: 3MnO4 2- + 4H+ 2MnO4 - + MnO2 add 2 H2O Aha, now i remeber! Hope this helps!