Experiment 2: Analysis of an Iron Coordination Complex2/25/2019 Domenica DiStasioObjective: In experiment 1, we synthesized K3[Fe(C2O4)3]·3H2O. In this lab, our goal was to obtain evidence that the complex we made was in fact this. We analyzed the complex based on a series of oxidation/reduction reaction where we determined the mole ratio of Fe3+:C2O42- Data Collection: C2O42- AnalysisSample 1 Sample 21. Molarity of KMnO4 0.021M 0.021M2. Weight of Sample .200g .200g3. Final Buret Reading 26mL 38.4 mL4. Initial Buret Reading 0 mL 13mL5. Volume of KMnO4 dispensed. 26 mL 25.4 mL6. Moles of KMnO4 5.46E-4 mol 5.33E-4 mol7. Moles of C2O42-1.365E-3 mol 1.335E-3 mol8. Final Burette reading (2nd) 24.2 mL 27.5 mL9. Initial Burette reading (2nd) 20 mL 23 mL10. Volume of KMnO4 Dispensed 4.2 mL 4.5 mL11. Moles of KMnO4 from Titration 2 8.82E-5 mol 9.45E-5 mol12. Moles of Fe3+4.41E-4 mol 4.73E-4 molCalculations: Useful Molar Masses K2C2O4166.2 g/molFe(NH4)2(SO4)2· 6H2O 392.1 g/mol K3[Fe(C2O4)3]· 3H2O 491.1 g/mol Calculate the moles of C2O42- present from the molarity and volume of the KMnO4 solution.Titration 1: Sample 1Volume= 26 mL, Molarity of KMnO4 = 0.021MMoles of KMnO4: (0.021)(.026 L) = 5.46E-4 molMoles of C2O42-: (5.46E-4 mol)(5/2) = 1.365E-3 molSample 2Volume= 25.4 mL, Molarity of KMnO4 = 0.021MMoles of KMnO4: (0.021)(.0254 L) = 5.33E-4 molMoles of C2O42-: (5.33E-4 mol)(5/2) = 1.335E-3 molTitration 2: Sample 1Moles of KMnO4 :(.021)(.0042)=8.82E-5Sample 2Moles of KMnO4:(.021)(.0045)=9.45E-5Calculate the moles of Fe3+Sample 1 Volume = 4.2 mL, Molarity of KMnO4= 0.021 MNo. of moles of Fe3+: (4.2E-3 L)(0.021 M)= 5(8.82E-5)=4.41E-4Sample 2Volume = 4.5 ML, Molarity of KMnO4 =0.021 MNo. of moles of Fe3+: (4.5E-3 L)(0.021 M)=5(9.45E-5)=4.73E-4Determine the mole ratio of C2O42-:Fe3+Sample 1Moles of C2O42: 1.365E-3 molMoles of Fe3+: 4.41E-4Moles of Fe3+¿=1.365× 10−34.41× 10−4=3:1Moles of C2O42−¿¿¿ Sample 2Mole of C2O42-: 1.335E-3 molMoles of Fe3+: 4.73E-4 molMoles of Fe3+¿=1.33 ×10−34.73 ×10−4=2:8Moles of C2O42−¿¿¿ Discussion: The analysis preformed is consistent with the complex 3:1 ratio between the C2O42 and Fe3+ based on the ratio calculation performed above. This analysis is consistent with our complex being K3[Fe(C2O4)3]· 3H2O. The ratio is slightly off on Sample 2 because of inconsistency in human error in the lab. One of these could have been the fact that the solution over heated (placed on the hot plate for longer than it should have been) which could have affected the results.Another inconsistency in the experiment could have been not reading the burette accurately and therefore getting inaccurate volumes of KMnO4
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