Lab 9 Vitamin C - Lab Report Sheet for students and grading...

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Lab Report Sheet for students and grading rubricsLab 9. Determination of Vitamin C by Redox Titration1.Data and observations (46 points):Mass of KIO3: 1.103g(2 points)Table 1: Data of the standardization of sodium thiosulfate. You can solve the averageand standard deviation using Excel (22 points):Trial 1Trial 2Trial 3Trial 4Initial volume (mL)0.11 mL1.57 mL0.23 mL1.12Final Volume (mL)43.73 mL45.69 mL43.78 mL43.93DeliveredVolume(mL)43.62 mL44.12 mL43.55mL42.81Average (mL) andstandarddeviation(mL)43.52 ± 0.5Table 2: Data of the back titration of vitamin C You can solve the average andstandard deviation using Excel (22 points):Trial 1Trial 2Trial 3Trial 4Initial volume (mL)1.19 mL1.01 mL1.11 mL0.71 mLFinal Volume (mL)11.63 mL10.00 mL13.80 mL10.81 mLDeliveredVolume(mL)10.44 mL8.99 mL12.69 mL10.10 mLAverage (mL) andstandard deviation(mL)10.55 ± 1.552.Data treatment and calculations Pre-lab questions (22 points):(1)In the lab you use potassium iodate (primary standard, KIO3) for vitamin Cdetermination. What are the molar masses of these two substances (2×2=4 points)?
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(2)What is a back titration? How is the vitamin C concentration determined in thisexperiment by a back titration (3×2 = 6 points)?

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