3.0 3.5 A) C–H B) N–H C) O–H D) O–C E) O–N 10) Using the table of bond dissociation energies‚ the ΔH for the following gas-phase reaction is __________ kJ. A) -44 B) 38 C) 304 D) 2134 E) -38 11) The mole fraction of urea (MW = 60.0 g/mol) in a
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The percent yield of meso-1‚2-dibromo-1‚2-diphenylethane was calculated to be 66.36% and with a melting point of 235.1°C. Therefore‚ it can be concluded that this experiment was successfully conducted as the percent yield obtained is only 33.64% off from the equilibrium point‚ and because the melting point met the literature value. The percent yield for the product was less than 100%‚ indicating that were experimental errors‚ such as an undesirable side reaction‚ or more likely‚ an incomplete reaction
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synthesis of Acetaminophen is based on the amine group of p-aminophenol being acetylated by acetic anhydride to form an amide functional group. Acetaminophen is isolated as a crude solid which is then recrystallized to purify the product. Using melting point determination the recovered products purity is identified and can be compared to the theoretical value. In this experiment 3.0g of p-aminophenol along with approximately 10ml of deionized water will be heated in a water bath regulated at 65-75
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The unknown carboxylic acid’s melting point was 108°C according to the Mel-Temp machine. The melting point is the temperature at which a solid precipitate changes into its liquid form upon heating. The melting point of benzoic acid‚ the aromatic carboxylic acid was 122°C. Thus‚ the product contained impurities which caused the solid to melt at a lower temperature than the actual temperature. Pure solids typically melt at higher temperatures while impure solids melt at lower temperatures. This is
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the freezing point will be somewhat lower‚ and there will be a range of temperatures instead of a single temperature. PROBLEM To evaluate the samples‚ you will need a heating/cooling curve for pure Na2S2O35H2O that you can use as a standard. To create and use this curve‚ you must do the following. • Obtain a measured amount of pure Na2S2O35H2O. • Melt and freeze the sample‚ periodically recording the time and temperature. • Graph the data to determine the melting and freezing points of pure Na2S2O35H2O
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Determination of Melting and Boiling Point of different Organic Compounds Bakare‚ Abimbola Kristine‚ C. Professor Miranda Marilyn‚ school of chemical engineering and biotechnology‚ Mapua Institute of Technology‚ CHM145L-B11 ABSTRACT A melting point of a solid is the temperature at which the first crystal just starts to melt until the temperature at which the last crystal just disappears. Thus‚ the melting point (m.p.) is actually a melting range. The melting point of a substance depends
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Title: Separating the components of “Panacetin” Name: Ip‚ Wing Chung (Vincent) Lab Partner: Ma‚ Siyin Date: 2/3/2013 Introduction: The purpose of this experiment is to investigate the composition of compounds in Panacetin. Generally‚ it is made up of sucrose‚ aspirin and an unknown component‚ either acetanilide or phenacetin. SinceBy using different techniques‚ such as filtration‚ extraction‚ and evaporation‚ those three components have been isolated out‚ which is based on varies solubility
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pleasant flavor‚ innocuousness‚ smoothness during application‚ adherence and easy intentional removal. This work involved the development of a lip balm formulated with certified organic raw materials and the execution of stability tests: fusion point determination‚ evaluation of organoleptic characteristics (color‚ odor and appearance) and functionality evaluation (spreadability test). The formulation selected after the Preliminary Stability Test was submitted to the Normal Stability Test under
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The crude naphthalene had a melting point range of 85°-90° C while the 35.4% yield of pure naphthalene had a melting point range of 70°-76° C. Recrystallization was used to purify the salicylic acid. Recrystallization is the process of dissolving the original solid in a hot solvent and then allowing the solution to cool to let the solid crystallize again. The crude salicylic acid had a melting point range of 150°-153° C while the pure salicylic acid had a melting point range of 155°-158° C. (Percent
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Recrystallization Experiment 2: Recrystallization & Melting Point • Most important method for the purification of organic solids • Separation of compounds based on differences in solubility between the compound of interest and its contaminants • Basic technique: 1. dissolve impure sample in an "appropriate" hot solvent Part A: Choosing a Solvent Part B: Purification of Phenacetin 2. cool solution slowly to induce crystal growth 3. filter resulting mixture to isolate crystals Reading:
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