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Author Question: A student was in a hurry to leave the lab and recorded the melting point of the recrystallized ... (Read 34 times)

Kthamas

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on: Aug 23, 2018
A student was in a hurry to leave the lab and recorded the melting point of the recrystallized trimyristin right after washing the crystals with cold acetone. The melting point range was 4650C. Is this a good result? If not, explain what happened.

Question 2

What probably occurred if, after the recrystallization of trimyristin, the crystals had black particles dispersed throughout? What could be done at this point to correct the situation?


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maya.nigrin17@yahoo.com

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Reply #1 on: Aug 23, 2018
Answer to Question 1

This is not a good result. The melting point of trimyristin is reported to be 56-57 C. The problem is that the crystals were not allowed to dry long enough, and therefore any acetone that was adsorbed onto the crystals led to a depressed melting point.

Answer to Question 2

The filtration of the extract after treatment with activated carbon was not completely effective. The crystals should be dissolved in acetone and the solution filtered, making sure that all of the activated carbon particles remain behind on the filter. The filtrate can then be concentrated and allowed to undergo crystallization.


Kthamas

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Reply 2 on: Aug 23, 2018
Excellent

xiazhe

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Reply 3 on: Yesterday
Gracias!

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