This topic contains a solution. Click here to go to the answer
« previous next »

Author Question: You have isolated caffeine from the over-the-counter pharmaceutical called NoDoz and wish to purify ... (Read 51 times)

ashley

  • Hero Member
  • *****
  • Posts: 584
on: Aug 23, 2018
You have isolated caffeine from the over-the-counter pharmaceutical called NoDoz and wish to purify it by recrystallization. Using the data in Table E9.1, explain which solvent you would use and why.

Question 2

Extra-strength Excedrin is a combination of 250 mg acetaminophen, 250 mg aspirin, and 65 mg caffeine plus inactive ingredients that are insoluble in water and organic solvents. Using the data in Table E9.1, draw a flowchart to show how these three components could be separated using their solubility and acid-base properties. Hint: Caffeine is a nitrogen base similar in reactivity to diisobutylamine.


Related Topics

Need homework help now?

Ask unlimited questions for free

Ask a Question
Marked as best answer by a Subject Expert

gasdhashg

  • Sr. Member
  • ****
  • Posts: 335
Reply #1 on: Aug 23, 2018
Answer to Question 1

The best solvent would be ethanol. The solubility of caffeine in water is extremely high at 100C, meaning that we would only need to start with 1.5 mL of water for every 1 gram of caffeine. The problem is that, when the solution is cooled to room temperature and then to ice-bath temperatures, almost all of the caffeine will crystallize out of a very small volume of solvent. This makes separating the solvent from the crystals difficult. This is not the case with ethanol, where a fair amount of solvent is required to get 1 gram of caffeine to dissolve at higher temperatures

Answer to Question 2



ashley

  • Member
  • Posts: 584
Reply 2 on: Aug 23, 2018
:D TYSM

scikid

  • Member
  • Posts: 300
Reply 3 on: Yesterday
YES! Correct, THANKS for helping me on my review

« previous next »
 

Did you know?

The toxic levels for lithium carbonate are close to the therapeutic levels. Signs of toxicity include fine hand tremor, polyuria, mild thirst, nausea, general discomfort, diarrhea, vomiting, drowsiness, muscular weakness, lack of coordination, ataxia, giddiness, tinnitus, and blurred vision.

Did you know?

Although the Roman numeral for the number 4 has always been taught to have been "IV," according to historians, the ancient Romans probably used "IIII" most of the time. This is partially backed up by the fact that early grandfather clocks displayed IIII for the number 4 instead of IV. Early clockmakers apparently thought that the IIII balanced out the VIII (used for the number 8) on the clock face and that it just looked better.

Did you know?

Vaccines cause herd immunity. If the majority of people in a community have been vaccinated against a disease, an unvaccinated person is less likely to get the disease since others are less likely to become sick from it and spread the disease.

Did you know?

Over time, chronic hepatitis B virus and hepatitis C virus infections can progress to advanced liver disease, liver failure, and hepatocellular carcinoma. Unlike other forms, more than 80% of hepatitis C infections become chronic and lead to liver disease. When combined with hepatitis B, hepatitis C now accounts for 75% percent of all cases of liver disease around the world. Liver failure caused by hepatitis C is now leading cause of liver transplants in the United States.

Did you know?

Intradermal injections are somewhat difficult to correctly administer because the skin layers are so thin that it is easy to accidentally punch through to the deeper subcutaneous layer.

Animals of Hindustan monkeys called bandar that can be taught to do tricks Animals of Hindustan monkeys called bandar that can be taught to do tricks
Dish from Ecuador called "Cuy" Dish from Ecuador called "Cuy"
Angioplasty. One form is called balloon angioplasty, shown here. A balloon catheter is threaded into Angioplasty. One form is called balloon angioplasty, shown here. A balloon catheter is threaded into
Material safety data sheets (MSDS), now called safety data sheets (SDS), should be readily available ... Material safety data sheets (MSDS), now called safety data sheets (SDS), should be readily available ...
Cutaway Drawing of Tholos, The So-called Treasury of Atreus Cutaway Drawing of Tholos, The So-called Treasury of Atreus
A nerve cell (neuron) has extensions called dendrites A nerve cell (neuron) has extensions called dendrites
Video: Causes of Angina

For a complete list of videos, visit our video library