(A) A 0.376 g sample of an iron ore is dissolved in acid, and the iron reduced to Fe²⁺(aq) and then titrated with 41.25 mL of 0.02140 M KMnO₄. Determine the mass percent Fe in the iron ore.

(B) Another substance that may be used to standardize KMnO₄(aq) is sodium oxalate. If 0.2482 g Na₂C₂O₄ is dissolved in water and titrated with 23.68 mL KMnO₄, what is the molarity of the KMnO₄(aq)?

MnO₄^-(aq) + C₂O₄^2-(aq) + H⁺(aq) → Mn²⁺(aq) + CO₂(g) + H₂O(l)     (not balanced)