Melting Point Lab Report

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%

The primary goal of this laboratory is to correctly identify an unknown substance. To achieve this task, one may use various tests that reveal both chemical and physical properties of a substance. By comparing the results of a known substance and the unknown substance, one may eliminate alternative possibilities and more accurately predict the undisclosed compound. Furthermore, by performing these tests, data can be collected and verified regarding chemical and physical properties of the unknown. Understanding the chemical properties of a known substance aids one’s understanding of the unknown based on comparative analysis of the results of the tests.

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.

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.

Dimethyl Fumarate was not successfully created during the course of this particular experiment, likely because of a failure of the bromine to mix with the other components of the test tubes. It was observed that the bromine had formed a separate fraction at the top of the rest of the test tube contents, and because of this the necessary reaction could not occur in substantial amounts for a precipitate of dimethyl fumarate to form. The amount of bromine that was in contact with the dichloromethane and dimethyl maleate was simply too small for a significant reaction to occur. The data discussed below is sourced from Alexander Boley. Alex reported the melting point range to be 94-97°C, with an accepted range of 102-105°C. The lower boiling point is most likely due to the compound not being dried sufficiently before the melting point was tested. Alex also reported isolating 0.348 grams of dimethyl fumarate. Since he utilized 0.5 g of dimethyl maleate solution, and the accepted density of dimethyl maleate is 1.153 g/ml, the theoretical maximum amount of dimethyl fumarate that could have been obtained is 0.5765 g; dimethyl fumarate would be present in the same amounts as it's steroisomer because of their identical constitution, so dimethyl maleate's density is a valid input for calculating the final amount of product. The result indicates that his percent yield was 60.36%. The percent loss indicated could be attributed to

4. The melting points of the solids were tested by placing them in crucibles and heating them using a hot plate.

We first, determined the percent recovery of both vanillin and unknown and then determined the melting range of both compounds. Determining the melting point range, verifies whether or not students purified the compounds properly. Pure compounds tend to have smaller and higher melting points than the original compound. Students worked individually when determining the melting range of vanillin—we were to determine the melting ranges of crude vanillin and the recrystallized vanillin made in the first lab. Moreover, students worked in pairs when determining the melting range of the unknown by using a commercial apparatus. For both solids, we watched the crystals melt. We recorded the temperature at which the solid first began melting and when the solid was completely

Objective: The objective of this experiment is to use acid-base extraction techniques to separate a mixture of organic compounds based on acidity and/or basicity. After the three compounds are separated we will recover them into their salt forms and then purify them by recrystallization and identify them by their melting points.

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 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.

The purpose of this experiment is to identify an unknown substance by measuring the density and boiling point. I will be able to conclude which substance is my own from a list of known options stating what its real boiling point and density is.

Have you ever wondered why a fire burns orange, or why a lighter burns blue towards the bottom of the flame? If we take a quick step back, this is mostly due to a chemical reaction that is known as the “specific heat”. This must be achieved (as well as the other two properties that every fire is required to possess in order to burn) in order for a flame to become present. After this specific heat is reached, a chemical reaction occurs and turns the fuel source of the fire into a vapor. The aspects that are required for a flame to be created are a heat source, some sort of fuel, as well as some sort of oxidizing agent. The only way that a change in flame color can be observed is by manipulating the fuel source. After we manipulate the source

The beaker was slowly heated on a hot plate with low stirring until most of the stilbene was dissolved. 0.4 g of pyridinium tribromide was measured and added to the beaker after 5 minutes of heating. Small amounts of ethanol were used to clean the sides of the beaker. The beaker was heated for an additional 10 minutes on low temperature. An ice bath was prepared. The beaker was removed from the hot plate and left to cool to room temperature. Once at room temperature, the beaker was placed in the ice bath for 15 minutes. The solid product was collected through vacuum filtration and the product was weighed and a melting point was taken. Waste was disposed of in the correct waste bins and lab bench was cleaned

Overall, the experiment succeeded that the metals show the theoretical properties. Differences existed in the mathematical calculation of the actual length. These differences, however, it can be accounted for by experimental error; more over there are uncertainty on purity of the

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