1) Commercial Aspirin tablets used in this lab contained 325mg of active ingredi
ID: 987448 • Letter: 1
Question
1) Commercial Aspirin tablets used in this lab contained 325mg of active ingredient. Calculate the percent difference of your result vs this true value. % difference = (Measured - True)/True * 100%
2) If DI water was used to calibrate the spectrometer instead of iron (III) chloride solution how would this have affected the reported absorbance of the solutions? (Increased, Decreased, unaffected) Briefly explain.
3) If finger prints were not removed for the sample cuvettes before measuring how would this have affected the reported absorbance of the solutions? (Increased, Decreased, Unaffected) Briefly explain.
Part Il and III: The Standards 2] Standard Solution 1 3] Standard Solution 2 4] Standard Solution 3 5] Standard Solution 4 6] Standard Solution 5 7] Construct a Calibration graph of Concentration VS Absorbance with a trendline equation 0.000444 0.651 0.000352 0.606 0.0002664 0.557 0.0001776 0.324 0.0000888 0.221Explanation / Answer
(1) Measured mass of Aspirin in tablet = 322 mg
True mass of Aspirin in tablet = 325 mg
% difference = (Measured - True)/True * 100% = ( 322 - 325 ) / 325 * 100% = 0.92% ( Ignore the negative sign)
(2) If DI water was used to calibrate the spectrometer instead of iron (III) chloride solution then absorbance would have decreased because absorbency measurements should only come from aspirin-Fe complex.
(3) Absorbance is basically the difference between the full spectrum of the beam, before it passes through the sample, and the detected light, after it passes through the sample. The sample solution is taken in a cuvette. In general, a clean cuvette doesn't absorb any light. However, cuvettes with fingerprints may absorb light due presence of dirt and oil. This ultimately decreases the absorbance value.
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