Identifying a Constituent of Panacetin Essay

1084 Words Nov 11th, 2011 5 Pages
Emily Davis
Partner: None
Chemistry 253- TA: Alma Wellensiek
Lab 3: Identifying a Constituent of “Panacetin”
9/15/2011

Purpose: The purpose of this experiment is to determine the unknown component of Panacetin.

Theory: Panacetin is an analgesic (pain reducing) and antipyretic (fever reducing) drug that is sold in drug stores. However, there is a suspicion that this bottle may be counterfeit, not containing the chemicals that it should. Panacetin should be made up of about 50 percent of the unknown component that we previously separated out of Panacetin for testing. We suspect that this unknown compound is either acetanilide or phenacetin, both of which can be toxic to humans. It is very important that this component is
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When I was making the mixtures to put in the capillary tubes, another clue was given that the unknown was in fact phenacetin. Pure acetanilide was a brownish color, as compared to both pure phenacetin and the unknown, which were both white. After placing the capillary tubes in the MelTemp, it became clear that the unknown was phenacetin. Acetanilide, as expected, began melting far before the unknown or the phenacetin+ unknown mixture, beginning to melt at 92C and finishing at 104C. The unknown began to melt at 133C and was finished by 135C and the phenacetin and unknown mixture began melting at 134C and was totally melted by 137C. The small range and extremely close melting points give further evidence that the unknown is phenacetin.

Exercises:

1. (a) What is the minimum volume of boiling water needed to dissolve 0.200g of phenacetin?

Solubility of phenacetin in boiling water= 1.22g/ 100mL

(b) About how much phenacetin will remain dissolved when the water is cooled to room temperature?

Solubility of phenacetin in cold water= 0.076g/ 100 mL

(c) Calculate the maximum mass of solid (undissolved) phenacetin that can be recovered when the cooled solution is filtered.

0.200g-0.012g=0.188g Phenacetin remaining

2. An unknown compound ‘X’ is one of the four compounds listed in table 3.2. A mixture of ‘X’ with benzoic acid melts at 89C, a mixture of ‘X’ with phenyl succinate melts at 120C, and

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