Question

In: Chemistry

Tell how each of the following experimental errors will affect your ex- perimental results (yield, purity,...

Tell how each of the following experimental errors will affect your ex- perimental results (yield, purity, or both), and explain why. (a) You failed to dry the product completely. (b) You used enough water to recrystal- lize phenacetin, but your unknown was acetanilide. (c) In Experiment 2, you didn’t extract all of the aspirin from the dichloromethane solution.  please answer the following questions with good explantion and structure if there are sturcutres.

Solutions

Expert Solution

a) If the product is not dried properly, then water will remain trapped in the product. Therefore, the product will definitely register a higher mass (higher yield) and hence, the percent purity (defined as the actual mass of the product divided by the theoretical mass) will be high.

b) The structures of phenacetin and acetanilide are given below.

phenacetin

acetanilide

Due to the presence of –OCH3 group in phenacetin, phenacetin is less soluble in water than acetanilide. Consequently, if more water is used to re-crystallize the product (which was actually acetanilide), a greater proportion acetanilide will dissolve in water and will be lost. Thus, the yield of the product will be lower than expected.

c) Aspirin is an organic acid and hence, more soluble in water. However, being an organic compound, aspirin is soluble in dichloromethane as well. Consequently, if aspirin is not completely extracted from dichloromethane, then some amount of aspirin is lost with dichloromethane. Thus, the product will have a lower yield and hence, purity.


Related Solutions

How would the following experimental errors affect your experimental results while separating the components of a...
How would the following experimental errors affect your experimental results while separating the components of a counterfeit pharmaceutical (yield, purity or both) and explain why. A) you failed to dry the product completely. B)you used enough water to recrystallise phenacetin, however your Unknown was acetanilide. C)in experiment 1, you didn't extract all of the aspirin from DCM solution.
describe and explain the possible effect on your results of the following experimental errors or vibrations....
describe and explain the possible effect on your results of the following experimental errors or vibrations. In each case, specify the component(s) whose percentage(s) would be too high or too low if: a.)After adding DCM to Panacetin, you didnt stir the mixture long enough. b.) during the NaOH extraction you failed to mix the aqueous and organic layers thoroughly c.)you mistakenly extracted the DCM solution with 1M HCL rather than 1M NaOH. d) instead of using pH paper, you acidify...
Describe and explain the possible effect on your TLC results of the following experimental errors or...
Describe and explain the possible effect on your TLC results of the following experimental errors or variations: a) The analyte spots are too large (b) The analyte solution is too dilute.
Explain how each of the following errors would have altered your results. CLEARLY EXPALIN why your...
Explain how each of the following errors would have altered your results. CLEARLY EXPALIN why your calculations would be high, low, or unchanged. a. The pH buffers used to calibrate the pH meter were each 0.5 pH units high (4.5 and 7.5 rather than 4.0 and 7.0 respectively). b. You decided to take the pH after each addition of 5.0 mL of NaOH rather than after every 0.5 mL during the neutralization of your acid sample. c. While using the...
1) Indicate how each of the following errors would affect(increase, decrease, or no change) your calculated...
1) Indicate how each of the following errors would affect(increase, decrease, or no change) your calculated value for the molar volume of O2 at STP (assuming that you complete the experiment otherwise correctly). In each case, explain your answer. a. you forgot to subtract the vapor pressure of water in determining the pressure of O2 b. while heating your sample in the test tube your flame was improperly adjusted so that the black soot formed on the outside of the...
1) Indicate how each of the following errors would affect(increase, decrease, or no change) your calculated...
1) Indicate how each of the following errors would affect(increase, decrease, or no change) your calculated value for the molar volume of O2 at STP (assuming that you complete the experiment otherwise correctly). In each case, explain your answer. a. you forgot to subtract the vapor pressure of water in determining the pressure of O2 b. while heating your sample in the test tube your flame was improperly adjusted so that the black soot formed on the outside of the...
1. Explain how different experimental errors can affect the reported value of Keq.
  1. Explain how different experimental errors can affect the reported value of Keq. Clearly state why the reported value of Keq would be bigger or smaller than the actual value. Examples may include: a) You thought the spectrometer was set to read trasmittance/absorbance at a wavelength of 447 nm, but it was actually set at 520 nm. b) You thought you measured the transmittance/absorbance in a cuvetter with a 1-cm pathlength, but it was actually 1.5 cm. 2. Would...
Salt Hydrolysis Lab Suggest how various experimental errors would affect your calculated values of Pka, Ka,...
Salt Hydrolysis Lab Suggest how various experimental errors would affect your calculated values of Pka, Ka, and or molarity. Clearly explain whether the calculated value would be higher, lower, or no different than the actual value. Possible experimental errors may include: a) The pH buffers used to calibrate the PH meters were 4.5 and 7.5, whereas you thought they were 4.0 and 7.0 and calibrated the pH meters accordingly. b) You decided to take the pH after each addition of...
1. State and Explain how each of these errors would affect (high, low, no change) your...
1. State and Explain how each of these errors would affect (high, low, no change) your calculated values of solubility and Ksp. a) The saturated solution of Cu(IO3)2 is not filtered to remove undissolved Cu(IO3)2. b) The saturated solution of Cu(IO3)2 is filtered into a wet flask. c) You use only 5.00 mL of the saturated solution instead of 10.00 mL. 2. At the end point of a titration in the standardization of the Na2S2O3 solution (using KIO3), you have...
1. Clearly and carefully EXPLAIN how each of the following errors will affect the calculated percent...
1. Clearly and carefully EXPLAIN how each of the following errors will affect the calculated percent ion in your known (higher, lower, not affected). a) Some of the KMnO4 solution decomposed between the time you standardized it and the time you used it in your determination of iron. b) Your buret leaked during the permanganate-iron titration and some of the solution spilled onto the lab bench. c) You did not stop the titration until the solution in the flask was...
ADVERTISEMENT
ADVERTISEMENT
ADVERTISEMENT