Part III

Next, you will measure the visible absorption spectrum of the dye you synthesized in Part I.
A representative example of this process using product C is shown below.

You should take notes on this process regardless of the product you were assigned.
You can view the results for your specific product on the next page.

The video shows a medium beaker sitting in a sand bath. The beaker contains approximately 30 mL of transparent, red liquid and a boiling stick. A gloved hand holds a large test tube filled with clear liquid nearby. A pipette is used to transfer a single drop of the red solution from the beaker into the test tube. The top layer of liquid in the test tube instantly turns bright orange. The pipette is then used to suction liquid from the bottom of the tube and expel it into the top, mixing the solution and turning it a golden yellow. Next a plastic syringe is used to withdraw 1 mL of the solution from the test tube and place it in a second large test tube, already partially full of clear liquid. The pipette is again used to mix the solution, and more clear liquid is added from a graduated cylinder, followed by more mixing via pipette. Both large test tubes are then held up in front of a piece of white paper, revealing the difference in color (golden yellow vs. pale yellow). In the next shot, we see a portion of the pale yellow solution being pipetted into a small plastic cuvette. The cuvette is placed in the slot of a small black plastic box labeled “Go Direct SpectroVis Plus.” This box is wired to a LabQuest 2 device. A plastic stylus is used to press the “play” button on the LabQuest 2 screen, which brings up a message reading: “This collection will overwrite the latest run. Do you wish to store or discard the latest run?” The stylus is used to select the “Discard” option, and which point we see a plot of Absorbance vs. wavelength (nm). The plot contains two peaks above an otherwise mostly flat line. The first peak has an absorbance value of approximately 0.25 and coincides with the light blue portion of a rainbow superimposed on the screen. The second peak has an absorbance value of approximately 0.075 and coincides with the white portion of the screen to the right of the red end of the aforementioned rainbow. The stylus selects the “stop” button, then chooses the “Analyze” menu from the top of the screen, followed by the “Statistics” and “Abs” options, which reveals a panel on the right side of the screen that reads: “Abs 0.006; Statistics; min: 0.006 @ 852.80; max: 0.259 @ 471.00; mean: 0.054; std. dev: 0.072806; samples: 775; delta y: 0.253; delta x: 568.200; wavelength 852.80 nm.”

Choose your product below to view your custom absorption results.

Product A

Product B

Product C

Product D

Product E

Product F

Product G

Product H

Product I

Product J

Product K

Product L

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