3. An iron ore sample weighing 0.9132 g is dissolved in HCl (aq), and the iron is obtained as Fe2+ (aq). This solution is then titrated with 28.72 mL of 0,05051 M K2Cr2O7. What is the mass percent Fe in the ore sample? (30 points) Fe2+ (aq) + Cr2O72- (aq) Fe+ (aq)+ Cr3+ (aq)