LAB 22. Spectrophotometric Analysis of Copper- Help.docx - Spectrophotometric Analysis of Copper Experiment 1 Make a plot of absorbance readings for

LAB 22. Spectrophotometric Analysis of Copper- Help.docx -...

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Spectrophotometric Analysis of Copper Experiment 1 Make a plot of absorbance readings for each of the solutions, absorbance vs. wavelength. Use the following table to keep track of your absorbances. Your plots/graphs should look similar to the ones given below. Wavelength (x axis) Absorbance CuSO 4 (y axis) graph #1 Absorbance COCl 2 (y axis) graph #1 400 0.00 0.00 420 0.00 0.10 440 0.00 0.07 460 0.00 0.07 480 0.00 0.16 500 0.00 0.23 520 0.00 0.22 540 0.00 0.13 560 0.02 0.07 580 0.05 0.04 600 0.09 0.00 620 0.14 0.00 640 0.22 0.00 660 0.35 0.00 680 0.50 0.00 700 0.63 0.00 What was the highest absorbance for the CuSO4?_______ Make sure the spectrometer is set to this wavelength for Experiment 2. Experiment 2 I have already calculated the actual concentration of Cu2+ ion in your samples. This is a simple dilution using the following equation: (conc. of original solution )*(volume of standard Cu2+) = (concentration of dilute solution)*(total solution volume) CuSO4 (mL) HNO3 (mL) Cu +2 Concentration (Mol/L) (x axis) Absorbance (y axis) Cuvette 1 4 6 (0.06)(4)/(10)= 0.024 Cuvette 2 7 3 (0.06)(7)/(10)= 0.042 Cuvette 3 10 (0.06)(10)/(10)= 0.06 Make a plot(graph) of absorbance as a function of the copper (II) concentration [M] in each of the standards. Similar to the one below. Experiment 3 Determine the copper concentrations in your two unknown samples from the calibration plot. (Find the concentration that matches the measured absorbance of each sample.) Record this information. Absorbance Estimated Concentration Unknown 1 0.37 Unknown 2 0.52

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