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preiou5
questions.docxQuestions
1. Convert %T to absorbance and prepare a Beer’s Law plot using this data.
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Concentration of Various Samples |
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Sample Identification Code |
Concentration of M (mol/L) |
%T |
A = 2 - log(%T) |
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Q5000 |
4.00 x 10-4 |
17.9 |
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Q5001 |
3.20 x 10-4 |
25.0 |
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Q5002 |
2.40 x 10-4 |
35.7 |
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Q5003 |
1.60 x 10-4 |
50.2 |
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Q5004 |
8.000 x 10-5 |
70.8 |
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Questions
3. What is the concentration of M in these samples?
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Concentration of M |
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Sample Identification Code |
%T |
A = 2 - log(%T) |
A |
M |
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Q021015-01 |
43.7 |
0.35951856 |
0.36 |
0.000192 |
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Q021015-02 |
44.1 |
0.35556141 |
0.36 |
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Q021015-03 |
43.8 |
0.35852589 |
0.36 |
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Q021015-04 |
44.1 |
0.35556141 |
0.36 |
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Q021015-05 |
43.8 |
0.35852589 |
0.36 |
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4. What was their percent error?
5. Does Batch 021015 meet legal requirements?
Exercise 2
Observations
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Data Table 1: Concentrations of Blue Dye |
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Well # |
1 |
2 |
3 |
4 |
5 |
6 |
7 |
8 |
9 |
10 |
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Drops of Blue Dye Solution |
1 |
2 |
3 |
4 |
5 |
6 |
7 |
8 |
9 |
10 |
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Drops of Distilled Water |
9 |
8 |
7 |
6 |
5 |
4 |
3 |
2 |
1 |
0 |
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Calculated Concentration |
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Observations
(Only if colorimeter is used in this experiment.)
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Data Table 2: Dilution |
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Test tube Number |
Solutions |
Concentration (M) |
Concentration (ppm) |
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3 |
Starting dilution (100 mL water and drops of blue#1 dye) |
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2 |
1:1 Dilution (1 part water - 1 part starting dye solution) |
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1 |
2:1 Dilution (2 parts water - 1 part starting dye solution) |
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0 |
Zero standard – distilled water |
0 |
0 |
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Data Table 3: Resistance vs. Concentration |
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Zero standard |
2:1 standard |
1:1 standard |
Original dilution |
Commercial drink sample |
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Concentration (M) |
0 |
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Concentration (ppm) |
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Resistance, Ω |
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Resistance, Ω |
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Average Resistance, Ω |
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Exercise 3
Questions
Fully discuss answers to the following questions. Yes or No responses are not sufficient. A. Was your calibration curve as linear as you expected?
B. Did you experience any “drift” of the resistance readings?
C. What is the equation of your best-fit line?
D. What commercial drink did you analyze?
E. Assuming that the same commercial drink was analyzed in both colorimetry methods, how did the results compare?
F. Which technique should give more accurate results?
G. What are some of the potential sources for errors in this experiment
