In this lab we used melting points to
determine the purity of organic compounds. Pure compounds were
seen to have a sharp and narrow melting range, while impurities were seen to
cause the melting range to become lower and broader. We have in this experiment two different pure
solid, urea and trans-cinnamic acid, two compounds with similar melting point. Then we will determine
the melting point range of three mixtures of these two substances. The critical point of the Procedure was to
take glass tubing and fill it with 50-100 mg of powdered sample, then tab the
seal end of the tube on the table, insert the tube to the melting point
apparatus and keep my eye on the sample to note the start and the end of the
melting range. From table 1 I found
that the melting range for pure urea and Pure cinnamic acid are less than or
equal 2 which consider as pure samples. While the mixture of (75 urea – 25 C.A% ) and (25urea-75 C.A%) where more than 2 which consider
as impure samples. The error happens during the lab in the equipment, or the
eyes if they skip the start or the end milting point. We can minimize it by
using a good new equipment and re do the experiment. The objective of the experiment has achieved.

We familiarize the technique of melting point determination and we determined
the purity of a crystalline solid. According to the figure.1 which shows a graph of the average
temperature and the % mole fraction of urea, the Eutectic point nearly is 60C and
the average temperature 134C.

We Will Write a Custom Essay Specifically
For You For Only $13.90/page!


order now