REDOX help?

Question

FeS2 + Na2O2 ------------------> Na2FeO4 + Na2SO4 + Na2O

I can't do the red equation


O2 (-1) -------------->O4(-2)


O2 (-1) -------------->O4(-2)


O2(-1) -------------->O(-2)

Answer 1

Were you given the original equation? I'm not sure that it's correct. I don't think "Na2FeO4" is a compound.

As far as looking at the oxygen is concerned, you have:

O22- --> 2 O2-

(peroxide where you have 2 oxygen atoms, each with an oxidation number of -1 going to 2 oxide ions, each with an oxidaiton number of -2)

So, check the rest of the equation before you get too involved.