Mixed Melting Points

843 WordsSep 26, 20114 Pages
Organic chemistry 201 | Mixed Melting Points | Determination of an Unknown Solid | | [Type the author name] | 9/15/2011 | Purpose : The main purpose of this experiment was to identify an unknown compound/substance by performing multiple experimental melting point tests. Pure and impure solids were tested to see what affect pureness/impureness had on a melting point. Background: The melting point of a solid can be used to determine the purity of the solid. Pure samples usually have identical or similar melting points. Given this information, the identification of an unknown solid could be determined by comparing its experimental melting point to an accepted literature value of a known substance. Pure solids always have…show more content…
When the unknown was mixed with urea the range was 98.1-107.4, this is a low melting point as well as a wide melting point range. Since the unknown: urea mixture had a lower melting point and wider melting point range , the mixture was impure, therefore the unknown was not urea. The unknown substance was found to be cinnamic acid. There were some possible experimental errors with the procedure for obtaining melting points. One error would be heating the sample too fast. If the sample was heated too fast it was hard to determine an accurate temp at which the sample started to melt and when it finished. Having too much or too little sample in the capillary tubes also could have affected the results. If too little of a sample was used, the sample was noted to have melted quicker, if too much sample was used it took longer to melt. Whether the sample was packed tight in the capillary tube or not also affected the results. If it was packed too loosely some of the sample was noted to be melting more quickly than the rest. When the sample was packed tightly it was harder to determine the exact moment that the crystals started to
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