Answer to Question #260289 in General Chemistry for Sharon

Question

A 0.550 g sample is dissolved in water and conducted the following experiment to find its % w/w V3+ in the sample:

Step 1:

25.00 ml of 0.0400M K2C2O4, after acidification, is used to find the end point, requiring 22.70 ml of KMnO4(aq) for complete reaction. The reaction as follows:

__C2O42- (aq) +__MnO4- (aq) + __ H+ (aq) → ___CO2(g) +___Mn2+ (aq) + __H2O(l)

(unbalanced)

Step 2:

The aqueous solution of 0.550 g of the sample, after acidification, requiring 35.20 ml of the same KMnO4(aq) for complete reaction. The reaction as follows:

___V3+ (aq) + ___MnO4- (aq) + _____ H2O (l) → ___VO2+ (g) +___Mn2+ (aq) + ____H+(aq) from sample. (unbalanced)

(a) Balance the equations above. (3 marks)

(b) Calculate its % w/w V3+ in the sample. Show your calculation steps clearly. (7 marks)

Answer 1

___V3+ (aq) + ___MnO4- (aq) + _____ H2O (l) → ___VO2+ (g) +___Mn2+ (aq) + ____H+(aq)

__C2O42- (aq) +__MnO4- (aq) + __ H+ (aq) → ___CO2(g) +___Mn2+ (aq) + __H2O(l)