2. Suppose that a student does not remove fingerprints from the cuvette before t

Question

2. Suppose that a student does not remove fingerprints from the cuvette before the absorbance of a test solution is measured. What would happen to the measured absorbance? Would the calculated mass of iron in the table for this trial be too large, too small, or unaffected by this error? Explain why. 3. Suppose a student analyzes an unknown tablet as described in the experimental procedure and the absorbance of the resulting Solution 3 is determined to be 1.250, which is higher than any value from your standard curve. What might the student do in order to determine the amount of iron in this sample without making new standard solutions?

Explanation / Answer

Part A. Fingerprints might cause incident light to reflect, refract or bend the light. This wil lower the transmittance and higher absorbance will be observed.

The mass of iron calculated would be too large. Because of above error, the absorbance will be higher. Since absorbance is related to concentration, the concentration will be higher. Hence mass will be large.

Part B. . Dilution is the solution for this higher absorbance. You need to take lesser solution and dilute with water and buffer reagents. Then absorbance needs to be measured and concentration can be determined from absorbance versus concentration graph.

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