1) Fill up Table 1 that illustrates how the calibration solutions and the unknown solution were...

  

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1) Fill up Table 1 that illustrates how the calibration solutions and the unknown solution were prepared and the absorptions (A) of these solutions. Table 1 V= 0.05M I, Solmison -0. 05M lodine solution concentration / x10 mol dm3 Volume of 0.5 mM iodine solution / ml or volume of unknown iodine solution X/ mL Volume of the flask / ml Absorption (A) 0.01 0.04 0.08 0.12 0.14 100 100 O DE Dle 421 100 2) Plot an absorbance versus concentration (in mol dm) graph using the data obtained (Note: You can do it either manually (scan it in for electronic submission) or electronically, e.g. by using Excel). 3) From the curve determine the concentration of the unknown iodine solution X. 4) What was your estimation by eye of the concentration? Comment on how different it is from the measured one. From your absorbance readings, A, and using equation 2, calculate e287.8nm for the iodine-KI solutions used to prepare your standards and the unknown. Assume I= 1cm. Report your results by filling Table 2. A = ECI %3D Table 2 lodine solution concentration /x103 mol dm3 dm /mol.cm Average value of ɛ 0.01 0.04 D.O61 0.379 0.08 0.12 0.14 6421 0:031 5) Explain why, in the preparation of the iodine stock solution, it was necessary to add solid iodine to a solution of potassium iodide for full iodine dissolution to occur. What is the significance of KI in this? 6) Why do you think the unknown iodine solution X had to be diluted by a factor of two prior to analysis? OTAO e 1) Fill up Table 1 that illustrates how the calibration solutions and the unknown solution were prepared and the absorptions (A) of these solutions. Table 1 V= 0.05M I, Solmison -0. 05M lodine solution concentration / x10 mol dm3 Volume of 0.5 mM iodine solution / ml or volume of unknown iodine solution X/ mL Volume of the flask / ml Absorption (A) 0.01 0.04 0.08 0.12 0.14 100 100 O DE Dle 421 100 2) Plot an absorbance versus concentration (in mol dm) graph using the data obtained (Note: You can do it either manually (scan it in for electronic submission) or electronically, e.g. by using Excel). 3) From the curve determine the concentration of the unknown iodine solution X. 4) What was your estimation by eye of the concentration? Comment on how different it is from the measured one. From your absorbance readings, A, and using equation 2, calculate e287.8nm for the iodine-KI solutions used to prepare your standards and the unknown. Assume I= 1cm. Report your results by filling Table 2. A = ECI %3D Table 2 lodine solution concentration /x103 mol dm3 dm /mol.cm Average value of ɛ 0.01 0.04 D.O61 0.379 0.08 0.12 0.14 6421 0:031 5) Explain why, in the preparation of the iodine stock solution, it was necessary to add solid iodine to a solution of potassium iodide for full iodine dissolution to occur. What is the significance of KI in this? 6) Why do you think the unknown iodine solution X had to be diluted by a factor of two prior to analysis? OTAO e

Answer rating: 100% (QA)

1 Tube Concentration M Absorbance 1 002 0061 2 008 0379 3 016 0386 4 024 0414 5 028 0421 2 3 From th... View the full answer