Lab Exam Final questions 1) What is Recrystillization? Explain in detail the pri
ID: 706604 • Letter: L
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Lab Exam Final questions 1) What is Recrystillization? Explain in detail the principle involved in it? 2) What is the importance of melting point? what is the instrument set up and explain the role of melting point in synthesis? 3) What is the reaction type in acetaminophen? how did you prepare it in a lab? 4)What are butane conformers? draw the different conformers of butane with varying energies? 5) Simple distillation and Fractional Distillation processes? Explain with diagram? 6)What is the substitution reaction and give an example? 7)How do you extract the organic liquid from the aqueous solution? 8)Name some bases, solvents and drying agents used in your lab experiments? 9) What are the tests for unsaturation? 10) Name any elimination lab experiment that you have performed? with a detailed chemical equation?Explanation / Answer
Answer 1: Recrystallization is the technique to purify a compound especially while synthesising a compound using a chemical reaction. It is done by taking a small amount of substance to be purified in a clean china dish and small volume of solvent is added. The solvent should be such that the substance should be partially soluble in it at room temperature and when heated should dissolve to form saturated solution. This solution upon cooling gorms pure crystals of the substance and the rest sloution is decanted.
Answer 2: The melting point is a physical property and is used for identification of a compound. In a chemical reaction when a new compounds are formed from two reactants then the melting point of the new compound is checked and compared with the two reactants to see whether the reaction is complete or not as the melting point of the starting matetials and the final product usually differs. If we are synthesizing a known compound then the melting point can be compared from the reference book to confirm the formation of the product. If melting point is not nearby the limit, this means impurities are present.
In a melting point apparatus the one sided sealed capillary tube filled with the substance is inserted while inserting a thermometer also. We check the point at which substance starts melting till the process is complete to record the melting range.Answer 2: The melting point is a physical property and is used for identification of a compound. In a chemical reaction when a new compounds are formed from two reactants then the melting point of the new compound is checked and compared with the two reactants to see whether the reaction is complete or not as the melting point of the starting matetials and the final product usually differs. If we are synthesizing a known compound then the melting point can be compared from the reference book to confirm the formation of the product. If melting point is not nearby the limit, this means impurities are present.
In a melting point apparatus the one sided sealed capillary tube filled with the substance is inserted while inserting a thermometer also. We check the point at which substance starts melting till the process is complete to record the melting range.
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