Melting Point Range Lab Report

I would have liked to do one more trial on each mixture for melting point analysis to confirm that my results were consistent. Furthermore, I would go back and repeat the second experiment to avoid adding HCl to the organic layer in order to separate an accurate weight of the unknown solid and ensure that the purity of the unknown is unaffected by an accidental HCl addition. I am unsure if my results are truly accurate due to the HCl addition and other errors, which means that the experiment would need to be repeated multiple times in order to report a consistent result. In conclusion, this experiment covered the techniques of recrystallization and melting point analysis, both of which are based on understanding physical properties such as water solubility and melting point.

The objective of the experiment “Keeping it Liquid” was to figure out what it takes to keep a compound in a liquid form which caused a phase change. A phase change is when a substance changes from one state or phase to another. There are three main phases that normally occur and they are called Evaporation, Deposition, and Melting. Evaporation is where a liquid changes to a gas. An example of evaporation is when water drops form on the glass of a cold drink on a warm day. Deposition is where a gas vapor goes directly into the solid phase without becoming a liquid first. An example of Deposition often occurs on windows during the winter months. While Melting is where a solid turns into a liquid. Melting occurs when ice turn into a liquid when

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.

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

Perform the following with three 0.05g samples of unknown and the following solvents: methanol, water and toluene

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 unknown substances by finding certain properties that this substance has. Like the density,melting point and the boiling point with these we are able to identify the unknown liquid and unknown solid that we are given. In order to get the density of a liquid we are first going to divide the mass of the liquid by the volume of the liquid in order to get us the density. In order to get the density of a solid we are going to divide the mass of the solid by the volume of the solid in order to get us the density of the solid. Next we are going to want to find the boiling point of a liquid we find this by placing a thermometer and test tube into a beaker with some water in it. Then we boil it and record the data we are going to want to record the start of the boiling and constant temp of the boiling then use this equation ( Start of boiling + constant temp of boiling ) / 2. This will give us our boiling temperature +/- 5 degrees. Finally we are going to want to find the melting point of a solid we do this by placing the tube in the device that determines the melting point of a solid. Then we

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.

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

From the table four appropriate simple tests can be conducted in order to determine the structure type and identify the four white powders. This includes conducting tests of melting point, flame color, solubility and the conductivity in water (H20). The melting point of a substance is the temperature at which the material changes from a solid to a liquid state. The determination of melting points is a form of identification and test method for organic substance. The melting point is an easy way measure and classify substances. Testing the flame color is an appropriate test as metal ions change the color of a flame when they are heated. Different metal ions give different colors to the flame. So flame tests can be used to identify the presence of a particular metal in a sample. Solubility is appropriate as a solvent a substance will dissolve in gives hints to its identity. Conductivity in water (H20) identifies if a substance is ionic or molecular. If a solution of compound and water has high conductivity level, the compound is ionic if not it is molecular.

According to Drexel, Trans – Cinnamic Acid has a melting point 133 – 134. The melting points that were obtained in the lab were very close to the true melting points of each substance. The color ofeach substance did not change however the state of the substances changed. The substances went from a solid to a liquid and then back to a solid. The process of using a digimelt to melt different substances and finding their melting points is a useful technique because it allows chemists to identify substances and if that substance is pure.

Melting point and Boling point are two fundamental physical properties that are commonly used to identify unknown compounds, to verify already known compounds, and to determine the purity of compounds.2 If the compound is a solid, the procedure for melting point determination is followed. However, if it is a liquid a boiling point technique must be performed, such as distillation or refluxing.2

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