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

Author Question: A student started with 100 mg of an unknown solid and recrystallized this material from water. The ... (Read 56 times)

Destiiny22

  • Hero Member
  • *****
  • Posts: 557
on: Aug 23, 2018
A student started with 100 mg of an unknown solid and recrystallized this material from water. The weight of the crystals they isolated was 27 mg. Explain why the student might have obtained this result and what the student can do to try to correct the problem.

Question 2

A student started with 100 mg of an unknown solid and recrystallized it from water. The weight of the crystals isolated was 120 mg and the melting point range was very broad and lower than the literature value. Explain the problem that the student encountered and how the student can solve it.


Related Topics

Need homework help now?

Ask unlimited questions for free

Ask a Question
Marked as best answer by a Subject Expert

14vl19

  • Sr. Member
  • ****
  • Posts: 310
Reply #1 on: Aug 23, 2018
Answer to Question 1

The hot solution was probably not saturated and therefore recrystallization would be inefficient. They should attempt to obtain a second crop of crystals by concentrating the mother liquors.

Answer to Question 2

The crystals are most likely wet with the solvent used for recrystallization. The student should let the crystals dry until the weight is constant and then recheck the melting point.


Destiiny22

  • Member
  • Posts: 557
Reply 2 on: Aug 23, 2018
Great answer, keep it coming :)

Jossy

  • Member
  • Posts: 336
Reply 3 on: Yesterday
Wow, this really help

« previous next »
 

Did you know?

The top five reasons that children stay home from school are as follows: colds, stomach flu (gastroenteritis), ear infection (otitis media), pink eye (conjunctivitis), and sore throat.

Did you know?

Essential fatty acids have been shown to be effective against ulcers, asthma, dental cavities, and skin disorders such as acne.

Did you know?

More than 2,500 barbiturates have been synthesized. At the height of their popularity, about 50 were marketed for human use.

Did you know?

An identified risk factor for osteoporosis is the intake of excessive amounts of vitamin A. Dietary intake of approximately double the recommended daily amount of vitamin A, by women, has been shown to reduce bone mineral density and increase the chances for hip fractures compared with women who consumed the recommended daily amount (or less) of vitamin A.

Did you know?

The National Institutes of Health have supported research into acupuncture. This has shown that acupuncture significantly reduced pain associated with osteoarthritis of the knee, when used as a complement to conventional therapies.

Chinese Water Deer Chinese Water Deer
Nursing student will find it funny Nursing student will find it funny
Effects of Differences in Solute Concentration on the Movement of Water Molecules Effects of Differences in Solute Concentration on the Movement of Water Molecules
Collage of Student Faces Collage of Student Faces
Water provides adequate hydration Water provides adequate hydration
Primary material used for HEADERS Primary material used for HEADERS
Video: Cataract

For a complete list of videos, visit our video library