Question

The amount of iron in a meteorite was determined by a redox titration using KMnO4 as the titrant. A 0.4408 g sample was dissolved in acid and the liberated Fe3+ quantitatively reduced to Fe2+. Titrating with 0.0220 M KMnO4 requires 41.38 ml to reach the end point.

Unbalance reaction: Fe2+ + MnO4- → Fe3+ + Mn2+.

Determine the % w/w Fe2O3.

Answer 1

Balance the equation.
mols MnO4^- = M x L = ?
Convert mols MnO4^- to mols Fe using the coefficients in the balanced equation.
g Fe = mols Fe x molar mass Fe
%Fe = (g Fe/mass sample)*100 = ?
Post your work if you get stuck.

Answer 2

im confused on how to balance

Answer 3

Mn goes from +7 in MnO4- to +2 in Mn.
Fe goes from +2 to +3.
Here is a site all about redox and balancing redox equations.
http://www.chemteam.info/Redox/Redox.html