Spectrophotometer - Colorimeter Lab Essays - Spectroscopy, Chemistry

Spectrophotometer - Colorimeter Lab Essays - Spectroscopy, Chemistry Spectrophotometer - Colorimeter Lab Dev Brar Jonathan Badonsky, Melissa Berberi, Maja Bekcic, Miranda Adam, Madeleine Chang, Danny Kelly SCH3US-01 Sawicki October 1, 2017 Part 1: Purpose: To use colorimetry to determine the maximum light absorbance for a colored solution. Hypothesis: The red aqueous solution will have a maximum absorbance in the range of 480 nm to 560 nm. Whereas the blue aqueous solution will have a maximum absorbance somewhere in the range of 600 nm to 640 nm Materials: Table 1: Materials used in part 1 of colorimetry lab Apparatus Chemicals spectroscope ( 3nm) Distilled Water 2 Plastic Pipettes Aqueous solutions of food coloring 2 Test Tubes 2 Cuvettes (3.50 0.25ml) Small spectroscope ( 3nm) Procedure: Spectrometer was assembled and calibrated using test tube filled with distilled water spectroscope was set to wavelength 400 nm Second test tube was filled with blue aqueous solution and was placed into spectroscope Results were recorded for the absorbance of the solution at 400 nm Steps 1 through 4 were recorded at wavelengths at intervals of 10 nm until a wavelength of 700 nm was achieved Solution was disposed of, spectroscope was turned off, and work place was cleaned Small spectroscope was assembled Small spectroscope was calibrated with a 3.500.25ml cuvette containing distilled water from a plastic pipette Second cuvette was filled with a red aqueous solution from a second pipette Cuvette was gently tapped multiple time on the label table until all bubbles had disappeared from the container Cuvette containing the red aqueous solution was placed in the small spectroscope Results were recorded for the absorbance of the solution in intervals of 10 nm from 400 nm 700 nm Solutions were dispossessed of, small spectroscope was turned off, and workplace was cleaned. Observations: Ta ble 2: Absorbance spectrum of red and blue solution between wavelength of 400 nm and 700 nm Wavelength (+/- 3nm) Absorbance of Blue Aqueous Solution Absorbance of Red Aqueous Solution 400 0.10 0.39 410 0.09 0.34 420 0.07 0.32 430 0.02 0.33 440 0.02 0.37 450 0.03 0.46 460 0.02 0.59 470 0.03 0.75 480 0.03 0.90 490 0.03 1.03 500 0.03 1.12 510 0.01 1.12 520 0.05 1.02 530 0.07 0.91 540 0.09 0.62 550 0.12 0.33 560 0.17 0.13 570 0.24 0.01 580 0.32 -0.04 590 0.39 -0.07 600 0.50 -0.09 610 0.60 -0.10 620 0.82 -0.10 630 0.88 -0.09 640 0.70 -0.09 650 0.42 -0.08 660 0.24 -0.04 670 0.12 -0.07 680 0.05 -0.07 690 0.02 -0.06 700 0.02 -0.07 Table 3: Qualitative Measurements Solution Color State Odour Red Aqueous Solution Red Liquid Odourless Blue Aqueous Solution Blue Liquid Odourless Graph 1: Absorbance of Red Aqueous Solution and Blue Aqueous Solution VS Wavelength Analysis: Based upon the observations, the wavelength and the predictions to agree. The red aqueous solution had the maximum absorbance at approx 510 nm (refer to graph 1) and the prediction states that the ax absorbance for the red aqueous solution will occur in the range of 480 nm to 560 nm. The blue aqueous solution had the maximum absorbance at approx 630 nm (refer to graph 1) and the prediction states that the ax absorbance for the red aqueous solution will occur in the range of 600 nm to 640 nm. The independent variable in this lab was the wavelength, and the dependant variable is this lab were the absorbance of both red aqueous solution and blue aqueous solution. Conclusion: The maximum absorbance for the red aqueous solution was found within the range of 480 nm - 560 nm agreeing with the hypothesis which states that the maximum absorbance will be found from 480 nm to 560 nm. The maximum absorbance for the blue aqueous solution was found within the range of 600 nm - 640 nm agreeing with the hypothesis which states that the maximum absorbance will be found from 600 nm to 640 nm Part 2: Purpose: To determine the concentration of a coloured solution by constructing a standard curve and by comparing the absorbance value of the unknown to the standard. Materials: Table 4: Materials used in part 2 of colorimetry lab Apparatus Chemicals Spectroscope (3 nm) Distilled water 8 Test Tubes Unknown Sample Plastic Pipettes Copper (II) Sulfate(aq) in