How do I determine how many moles of KMnO4 it takes to neutralize C2O4-?

Answer 1

You can't without knowing how much of the oxalate you have; however, you may find the ratio of oxalate to permanganate from the below.
2MnO4^- + 5C2O4^2- + H^+ ==> 10CO2 + 2Mn^2+
The above equation isn't completely balanced but you may complete it if you wish; however, the redox part (the part that matters in this equation) IS balanced. To work the problem balancing the redox part is all that is required. But be careful, some profs won't let you get away with that.
Use the coefficients in the above equation to convert mols C2O4^2- to mols MnO4^-