Physical Properties Of A Compound

No correction had to be made to the melting points because the standard melted in the range labeled on the bottle. The melted point observed is the correct melting point.

Discussion The third experiment of the semester involves identifying an unknown component of Panacetin, a common pain relief medication, separated and precipitated in the previous experiment. Although Panacetin’s label reports this third ingredient as Tylenol, there is controversy over the true classification of the third substance. This Panacetin label also reports that the unknown constituent makes up 50% of the composition of Panacetin, compared to aspirin’s 40% composition and sucrose’s 10% composition, meaning that it is currently unknown what half of the drug people ingest is identified as. Research results have failed to repeatedly show that the third component of Panacetin is Tylenol, which leads to the hypothesis

Melting Point Data Table Compound Aspirin Caffeine Salicylamide Actual MP (ºC) 93 - 98 260 - 262 96 - 102 Expected MP (ºC) 135 236 140 Percent Error (%) ~30% ~12% ~30%

We packed the powdered alum into a capillary then dropped it onto the lab table to make it move to the bottom. My group then strapped the tube onto a thermometer using a rubber band. Next, we clamped the thermometer with the capillary tube onto a ring stand with a rubber stopper. We dipped the thermometer and tube into a Thiele melting point tube that held silicon oil inside of it. My group heated the tube with a bunsen burner and waited for the powdered alum to melt from the capillary tube. We recorded the temperature at which the alum disappeared from the tube to get our melting point. This whole process was repeated to find a more accurate melting point than the first

Discussion: As seen in the melting point determination, the average melting point range of the product was 172.2-185.3ºC. The melting points of the possible products are listed as 101ºC for o-methoxybenzoic acid, 110ºC for m- methoxybenzoic acid, and 185ºC for p- methoxybenzoic acid. As the melting point of the sample

Melting points are indicative of identifying an unknown product and the level of impurity the product contains. In this case, the possible identity of the product based on its melting points are determined by comparing the obtained melting points of the product to the melting points of the five possible products. Two mini capillaries, containing the product only, were used to determine the product’s melting point. For one mini capillary, the temperature range was 132.1-134.2℃, and the product’s melting point for the second minicapillary ranged from 135.1-137.5℃. In addition, melting points were obtained with the product mixed with meso-hydrobenzoin. The temperature range was 135.0-136.0℃ and 135.0-137.5℃. Although the recorded melting point values fall into the racemic range, but the results still indicate that the product is a meso-hydrobenzoin. The melting point values for the product mixed with the meso-hydrobenzoin standard explains that it is unlikely that the product is racemic. The melting point values were two degrees from each other due to the meso-hydrobenzoin standard making

Melting range would be closely related to a mixed sample whose constituents are most identical. In other words, melting point will have a wide range and would be below 200°C and above 95°C.

In order to discover the melting point range of Unknown 33A, a Digimelt was utilized. Melting point is the temperature at which a crystalline structure changes from solid to liquid. By adding thermal energy, the structure changed from solid to liquid. The thermal energy increased the kinetic energy, which then overcame the intermolecular attractive forces between the molecules. This increase in speed allowed the molecules to move more freely. By identifying the melting point range of Unknown 33A, it narrowed the possibilities of the unknown by ruling out the compounds with melting points greater than ± 20°C from Unknown 33A’s melting point range.

If the unknown were mixed with an equal quantity of pure acetanilide, the melting point would have the same melting point. The addition of equal quantity of benzoic acid (melting point: 122°C) would make the mixture melt at a temperature below that of pure acetanilide. In fact, it would result in a lower, broader melting range, for instance, 95°C -

Procedure: This lab starts off by making sure the logger pro and temperature probe are in proper condition. Then, the data collection must be adjusted to 15 minutes and 12 samples/ min. After that a Bunsen burner must be set up by assembling a ring-stand, ring, and wire gauze, and a crack-less beaker is used to boil some water. First the beaker and the large watch glass need to be weighed and the mass has to be recorded using a triple beam balance. Next, the beaker with 200g of ice is placed on the ring stand, and immediately heated over medium flame. An important note is to make sure the flame is perfectly adjusted so the ice does not melt on the counter while trying to adjust the flame. Furthermore, place the temperature probe in the ice so it is not resting at the bottom of the beaker, it is best to secure it with a small clamp. Additionally, click the green start button on the computer and stir continuously with a glass rod until the ice is completely melted. Once the ice has melted which is somewhere between 3-5 minutes, the stirring rate will slow

This lab was conducted in order to determine the melting points of five samples: pure urea, pure trans-cinnamic acid, 90% Urea and 10% trans-cinnamic acid, 50% Urea and 50% trans-cinnamic acid, and 10% Urea and 90% trans-cinnamic acid. The melting points of the substances listed above were obtained by placing 1-2mm samples of each substance in a Mel Temp. From the obtained melting points, a binary phase diagram was created.

In determining the melting point range of the aspirin, a capillary tube (sealed at one end) was one-third-filled with the dried aspirin. The capillary tube and a thermometer were immersed in an oil bath. The temperature at which the solid started to melt and the temperature when the entire sample was completely liquefied were recorded as the melting point temperature range.

The objectives of this lab are, as follows; to understand what occurs at the molecular level when a substance melts; to understand the primary purpose of melting point data; to demonstrate the technique for obtaining the melting point of an organic substance; and to explain the effect of impurities on the melting point of a substance. Through the experimentation of three substances, tetracosane, 1-tetradecanol and a mixture of the two, observations can be made in reference to melting point concerning polarity, molecular weight and purity of the substance. When comparing the two substances, it is evident that heavy molecule weight of tetracosane allowed

Brittain, C. G. (2009). Using Melting Point to Determine Purity of Crystalline Solids. Retrieved from http://www.chm.uri.edu/mmcgregor/chm228/use_of_melting_point_apparatus.pdf

This tool is used in all stages of productions for the quality control of samples and its uses are very extensive which makes it distinctive from other