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Spectrophotometry
Course: Principles Of Chemistry I Laboratory (CHEM 109)
7 Documents
Students shared 7 documents in this course
University: York College CUNY
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Procedure for Spectrophotometry using Copper(II) Sulfate
Procedure-
1. First I obtain 6 cuvettes, four 25 mL Erlenmeyer flasks, and a 10 mL graduated
cylinder.
2. Then I obtain 10 mL of the standard 0.1M CuS solution. I put it in an𝑂
4
Erlenmeyer flask and label it A.
3. Using a pipet and a graduated cylinder, I transfer 5 mL of solution A into an
Erlenmeyer flask labeled B. I added 5 mL of deionized water into the flask and
swirl the solution to mix it. The concentration was 0.05M.
4. I transfer 5 mL of the solution from Erlenmeyer flask B into the Erlenmeyer flask
labeled C.Then I added 5mL of deionized water into the flask and swirl the
solution to mix it. The concentration was 0.025M.
5. I transferred 5mL of the solution from Erlenmeyer flask C into an Erlenmeyer
flask labeled D.Then I added 5 mL of deionized water into the flask and swirl the
solution to mix it. The concentration was 0.0125M.
6. I transfer the solution from each Erlenmeyer flask into its own individual cuvette.
7. Then I fill a cuvette with deionized water and use it to calibrate the spectrometer,
as instructed.
8. I place the cuvette with solution A in the spectrometer. I determine the
wavelength at which the maximum absorbance takes place. I recorded this
wavelength and set the spectrometer.
9. With cuvette A still in the spectrometer, I recorded its absorbance.
10. I place cuvette B in the spectrometer and recorded the absorbance of the
solution. Then I repeated this measurement with cuvettes C and D.
11. I obtained an unknown copper sulfate solution and recorded the number of
unknown. I filled the sixth cuvette with this solution, place it in the spectrometer
and record its absorbance.
12.When the measurements are completed, I prepare a calibration plot by plotting
the data for samples A-D on graph paper. Concentration is on the x-axis and
absorbance is on the y-axis.
