Experiment 02 – Spectrometry
CHM 1045L – Fall 2020 – PBSC
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Pre-lab Setup
Type out the chemical(s) used in this experiment, their hazards if applicable, and any other safety concerns associated with this experiment. Do this by searching “MSDS (chemical name)” on Google and looking at “Section 3: Hazards information” of any of the MSDS PDF documents that you find. Briefly paraphrase hazards.
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Type the procedure for this experiment in your own words. Feel free to use a bullet list (avoid huge paragraphs).
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Pre-lab Questions
1. Explain what would happen to the absorption of light in each of the following cases (Higher than it should be under normal conditions? Lower than it should be? Why?):
a. The student left a fingerprint on the cuvette when loading it into the spectrophotometer.
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b. A large air bubble in the solution was stuck to the inside of the glass in the cuvette.
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c. A colored cuvette was used instead of a clear one.
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2. Using the graph below, what is the concentration of a solution with an absorption of 0.269 when measured at 460 nm in a 1.0 cm cuvette. Remember units! Show your work for this problem on the last page of the form.
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Calculations/Work
1. Add a picture of your work for pre-lab question #2 below.
Data
Table 1. Fill out the following table with your collected data. Remember to graph using the values in M, not mM!
CuSO4 Concentration
Concentration in M
Absorbance (at 780 nm)
5 mM
10 mM
20 mM
40 mM
80 mM
Post-lab Questions
1. What was the trendline for your plot?
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2. What was the R2 value of your data?
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3. If a copper(II) sulfate solution showed an absorbance of 0.19 at 780 nm, what concentration is this solution? Remember units! Show your work for this problem at the end of the worksheet.
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Calculations/Work
2. Add a screenshot of your Excel graph below. Make sure it is correctly formatted as the instructions direct.
3. Add a picture of your work for post-lab question #3 below.
