Preview

Melting Point

Good Essays
Open Document
Open Document
930 Words
Grammar
Grammar
Plagiarism
Plagiarism
Writing
Writing
Score
Score
Melting Point
Mixture Melting Points

Abstraction
Determining the melting point is very significant in order to identify an unknown. In this experiment, measuring the melting point was done by using melting point apparatus. The melting point of the unknown sample #10 was 111.5˚C. There were two possible compounds which were dibenzoyl ethylene and o-Toluic acid because their melting points were 111.2˚C and 109.8˚C when each compound was mixed with the unknown. Therefore, the unknown #10 was dibenzoyl ethylene.
Introduction
The melting point is defined as the temperature at which the solid is in equilibrium with its liquid, and this characteristic is very unique, so a substance can be determined by the melting point. Determination of the melting point is very important technique in many areas of chemistry especially, in organic chemistry area because the melting point is really significant in order to identify the purity and the identity of a substance. Measuring the melting point is a fast and cost-effective technique which remains a strong link to the vast pre-instrumental chemistry literature, so the technique is still used for measuring purity of organic and pharmaceutical compounds. For that reason, determination of the melting point is more than just a classroom exercise in the organic chemistry lab.
Objective/Purpose
In this experiment, the identity of the unknown will be determined by measuring the melting point of the unknown and comparing the melting points of possible mixtures.

Background
The melting point of a material is the temperature at which the changes of the state from a solid to a liquid state, and is very unique physical constant for all substances. The mixture melting point is useful in confirming the identity of an unknown by mixing with known compound whose melting point is known because the melting point of the mixture tends to be almost the same temperature as the melting point of the known if they are the same substances. In addition, purity

You May Also Find These Documents Helpful

  • Satisfactory Essays

    Chem 1211K Lab Report

    • 1855 Words
    • 18 Pages

    The identification of the melting point of the organic acid was done to find another characteristic of the acid and to test the purity of the recrystallized pure acid. A 2-4 mm layer of unknown sample was placed into a capillary tube sealed on one end. Then the capillary tube was inserted into the side a Bibby Sterlin device. The plateau was set to 200°C on the melting point apparatus. Once the plateau temperature was reached, the sample was watched carefully. When the sample first began to melt and when it was fully melted was recorded. These numbers were the range of the melting point. A slow melting point of the unknown organic acid and a standard sample was completed next. A new plateau was set about 10°C lower than the observed melting point of the unknown sample. This time once the plateau was reached, the heating was no more than 1°C per minute. This gave a much more accurate read of both melting points. If the standard did not melt in the range listed on the label of the bottle, that meant the machine was not working properly. The standard sample and the unknown organic acid melted in their appropriate ranges.…

    • 1855 Words
    • 18 Pages
    Satisfactory Essays
  • Satisfactory Essays

    Exp 5 Soo Jin Park 73426

    • 326 Words
    • 2 Pages

    The purpose of this experiment is to determine the boiling point of a liquid and the melting point of a solid. It is useful to know the melting point and boiling point of a substance to identify whether it is pure or not. I could learn how to determine the melting and boiling point of a substance through its temperature when the acetamide turned into a liquid and bubbles emerged from the capillary tube in the Isopropyl alcohol.…

    • 326 Words
    • 2 Pages
    Satisfactory Essays
  • Good Essays

    Keep a small amount of the solid to determine its melting point. This is so we can use the melting point in our results afterwards. Make sure there is enough solid left in case the melting procedure goes wrong.…

    • 1079 Words
    • 5 Pages
    Good Essays
  • Good Essays

    If not already completed, crush a small amount of BHT and pack it into a capillary tube. Use a small rubber band to clamp the capillary tube to the thermometer, and fasten the thermometer to a ring stand. Fill a Thiele tube with water, and immerse the bottom of the capillary tube in it. Place the Thiele tube over a Bunsen burner and heat the substance until the BHT melts. As soon as evidence of melting occurs, record the temperature. Repeat the experiment using the BHT and the unknown substance.…

    • 602 Words
    • 3 Pages
    Good Essays
  • Powerful Essays

    During this experiment, we used recrystallization methods in order to help in the purification of the unknown solid, as well as drying and vacuum filtration. We then ground the unknown and combined it with different chemicals (such as acetanilide or phenacetin) and used the melting point ranges to determine the identity. We used the Mel-Temp method in order to measure the melting points. (It is important to remember that if a chemical is mixed with a differing chemical, the melting point is decreased drastically, but if it is mixed with a component very similar in chemical make up, the melting point will not differ much from the expected.)…

    • 1399 Words
    • 6 Pages
    Powerful Essays
  • Better Essays

    Panacetin Essay

    • 1093 Words
    • 5 Pages

    In each trial each separate component was placed in its own capillary tube, and then a 3rd capillary tube contained a 50/50 mixture of both ingredients. The results of their melting points occurred as is what the table says below.…

    • 1093 Words
    • 5 Pages
    Better Essays
  • Good Essays

    Hypothesis: Find the unknown substance by testing it out by heating it, pouring water, vinegar, and observing it .…

    • 944 Words
    • 4 Pages
    Good Essays
  • Powerful Essays

    In this experiment students were taking the slow melting point of their unknown compound. The tabulated list of all melting points of all students in the lab was created what was very helpful in finding a partner with the same organic solid based on the melting point data. Then with all possible matches students performed mixed melting point and the TLC experiment to find if they have the same retention factor (Rf). At the end of the lab students recorded the infrared spectrum (IR) of an organic compound by using FT-IR spectrometer. After the lab period a H NMR spectrum was given by TA.…

    • 862 Words
    • 4 Pages
    Powerful Essays
  • Good Essays

    Cyclohexane Lab Report

    • 1767 Words
    • 8 Pages

    Abstract: The purpose of this experiment is to determine the molar mass of an unknown solid. The freezing point of a solvent (Cyclohexane) was determined, and compare to the freezing point of Cyclohexane with the addition of two different concentration of unknown solid. The pure substance of Cyclohexane has defined physical properties. However, when a solute is added these properties are determined by the amount of solute added, also known as colligative properties. The temperature of the freezing point was lowered when the solid was added and it decreased as the concentration of the solid increased. The molality of the solute was determined, which was then used to calculate the molar mass of the solid for both trials. An average of the molar mass of…

    • 1767 Words
    • 8 Pages
    Good Essays
  • Good Essays

    Methanol Boiling Point

    • 569 Words
    • 3 Pages

    Explain results using scientific reasoning – link the relationship between the structure of the molecules and their melting and boiling points.…

    • 569 Words
    • 3 Pages
    Good Essays
  • Powerful Essays

    Hypothesis: If the freezing point depression of a solution of an unknown substance and BHT is measured, the molar mass of an unknown substance can be found.…

    • 908 Words
    • 4 Pages
    Powerful Essays
  • Good Essays

    Alum Lab Conclusion

    • 549 Words
    • 3 Pages

    The purpose of this laboratory was to use two different techniques to attempt to identify the melting point and the mole ratio of hydrated water to anhydrous aluminum, potassium, and sulfate of AlKSO4. The hypotheses were: if the alum was put in a capillary tube the melting point of alum will be able to be determined; and the water of hydration in alum crystals will be possible to determine if the alum is heated with a Bunsen burner.…

    • 549 Words
    • 3 Pages
    Good Essays
  • Satisfactory Essays

    Percent composition is defined as part divided by whole multiplied by 100. Water of hydrogen is defined as the amount of water produced into a molecule prepared in an aqueous solution. Molecular formula indicates the actual numbers and type of atoms in a molecule (notes).…

    • 275 Words
    • 2 Pages
    Satisfactory Essays
  • Powerful Essays

    Naphthalene Chromatography

    • 1479 Words
    • 6 Pages

    Finding the melting point of an organic substance is a practical and efficient way for scientists to identify an unknown substance or determine a known substance's level of purity. When organic substances are mixed together in varying degrees they take on a melting characteristic that is lower and broader than in its pure form. This property was manipulated in the lab to observe the various melting points of Naphthalene and Biphenyl when the percentage of composition was altered. A eutectic point of 45 °C at 52% Naphthalene was determined from the class data. An unknown crystalline substance was identified to be Benzophenone by mixing and finding its melting point with known substances.…

    • 1479 Words
    • 6 Pages
    Powerful Essays
  • Better Essays

    While waiting on the water to boil, retrieve a piece of unknown metal to be identified and record its ID letter and its mass. Once the mass of the unknown metal is recorded, put the metal into the boiling water. While waiting on the water and the metal to achieve the same thermal equilibrium, get a coffee cup and measure its mass. Then pour about 50mL of water into a coffee cup, measure the mass of the water and the coffee cup and then determine the mass of the water alone (mass of water and coffee cup – mass of coffee cup). Record the temperature of the boiling water on the hot plate with the metal and then record the temperature of the water in the coffee cup before adding the metal. Use the string attached to the metal to transfer the metal from the hot water bath to the calorimeter. Using a piece of cardboard to cover the top of the calorimeter, record the temperature of the water in the calorimeter. Repeat the experimental procedure three more…

    • 1030 Words
    • 5 Pages
    Better Essays