Quantitative Analysis Lab 7.docx - Lab 7 Determination of...

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Lab 7: Determination of Fe by UV-Vis Spectroscopy Olivia Lott Group 12 4/28/20 Purpose: To use a spectrophotometer to determine the absorption maximum. Data used to create a calibration curve where Beer’s law can be used to determine the molar absorptivity of the unknown sample. Reagents: 1. 1,10-phenanthroline solution 2. standard iron (II) stock solution 3. Hydroxylammonium chloride (HONH2·HCl) solution 4. Sodium acetate solution 5. Unknown: 12 mL for each group Procedure: 1. Into each of five 100 mL volumetric flasks, pipet 5, 10, 15, 20, and 25 mL of the standard iron (II) stock solution respectively. Use a combination of 5-, 10-, and 25-mL volumetric pipets. 2. Pour 50 mL of DI-water into a 6 th flask to serve as the “blank”. 3. Obtain 12 mL unknown sample as directed by instructor or TA, place in a 7 th flask and treat it in the same manner as the standards, as indicated below. 4. Line all seven 100-mL volumetric flasks in order: The blank, those with 5-25 mL of iron stock standard solution added, and the unknown sample. To each flask, pipet in order:

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