Beer’s Law Plot and Unknowns
Exercise 2 – Questions
1. Describe possible sources of error in this experiment.
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Questions 2 – 5 are based upon the following scenario:
A testing laboratory has been hired by a company called “Drug Company Q” to analyze a series of over-the-counter drugs that the company produces. In all of these over-the-counter drugs, the active ingredient is called “Active Ingredient M.” The laboratory technician collected the data from samples with known concentrations of Active Ingredient M. The data is shown below in Table 2.
Table 2. Known Concentrations of Active Ingredient M Drug
Sample Identification Code
Sample Concentration (M)
Absorbance
Q5000
4.00 x 10-4
0.750
Q5001
3.20 x 10-4
0.602
Q5002
2.40 x 10-4
0.447
Q5003
1.60 x 10-4
0.299
Q5004
8.00 x 10-5
0.150
The technician also collected absorbance readings for 5 over-the-counter drugs for review. The data collected for the 5 over-the-counter drugs is shown in Table 3.
Table 3. Absorbance Data for Over-the-counter Drugs
Sample Identification Code Absorbance
M21050-1 0.359
M21050-2 0.356
M21050-3 0.339
M21050-4 0.376
M21050-5 0.522
2. Create a Beer’s law plot and best fit line using the data in Table 2. Upload an image of the graph into Graph 4.
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3. Use the Beer’s law plot and best fit line to determine the concentrations for samples: M21050-1, M21050-2, M21050-3, M21050-4, M21050-5.
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4. The company reported that sample M21050-2 has an M concentration of 0.0003 M. Assuming that the results in Question 3 are 100% accurate and without error, is the company’s statement accurate? What is the percent error between the reported concentration and the concentration calculated in Question 3?
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5. By law, Drug Company Q must have an M concentration between 2.85 x 10-4 M and 3.15 x 10-4 M. Do all samples analyzed meet the legal requirements? Use the information from Question 3 to explain your answer.
0 Word(s)For more information on Beer’s Law Plot and Unknowns read :https://en.wikipedia.org/wiki/Beer%E2%80%93Lambert_law
