In chemistry it is important to understand the difference between physical and chemical changes. The objective of this experiment was to perform tests using heat or chemical mediators and observe the results for any physical or chemical changes. Various materials were heated or mixed, monitored and results recorded. Numerous chemical and physical changes were noted during the procedure. It was possible to distinguish between physical and chemical changes using scientific observations.…
The typical reagents that are used, such as elemental bromine and liquid bromine, are dangerous and highly corrosive, so this experiment used an alternative method of bromination.…
The Grignard reagents are alkyl magnesium halides, R-Mg-X were first introduced in 1900. These reagents are usually prepared by reacting one atom with one molecule or by other means magnesium and alkyl halide in the presence of dry alcohol free ether.…
References: 1. Carey, Francis A. "Grignard Reagent." Encyclopedia Britannica Online. Encyclopedia Britannica, 2012. Web. 12 Mar. 2012. <http://www.britannica.com/EBchecked/topic/246137/Grignard-reagent>.…
In this experiment two solutions were prepared for two kinetic runs. Solution #1 (50%ethanol 50% water) and Solution #2 (40% ethanol and 60% water) was added to another Erlenmeyer flask. Next, 0.10M of NaOH was filled up to the 0.00ml mark in two 50-ml burettes. Placing the flask containing solution 1 on the magnetic stirrer and clamp a burette containing 0.10M of NaOH above the flask. The two kinetic runs will be carried out one after another. A stir bar was placed into the flask containing solution #1 and 3-5 drops of phenolphthalein indicator solution to the reaction flask. To start the reaction, 4.91x10^-3 mol of alkyl halide to the stirring reaction mixture. The timer was started at the instant of this reaction. When enough HCl formed to neutralize the NaOH that was initially added, the pink color turned clear. The time was recorded.…
Phenylmagnesium bromide was expected product of this reaction however there are some by-product such as biphenyl which is formed from the reagent prepared reacting with unreacted bromobenzene.…
Procedure: The procedure followed was as is described in "Laboratory Manual for Organic Chemistry 2311," Fifth Edition, Jane E. Wissinger, Thomas Custom Publishing, Mason, Ohio, 2006. pp. 34-37. Modifications of the procedure included adding an additional 1.25 mL of bromobenzene to flask containing the magnesium before the start of the Grignard reaction, because of a broken stopcock which let all of the original 2.25 mL of bromobenzene into the flask initially. Then, this additional bromobenzene was slowly added to the flask dropwise in an attempt to start the reaction. However, because the reaction did not begin, the entire procedure up until this point was repeated, this time with an intact stopcock and just the 2.25 mL of bromobenzene as specified in the lab manual. A crystal of iodine was added in order to start the reaction. During the crystallization, as the solution was boiling and after four or five full pipets of petroleum ether were added, no cloudiness was…
Grignard reagents are good nucleophiles as well as strong bases (Weldegirma). It allows compounds to react with acidic compounds, therefor is must be free from acids as well as water during the desired reaction. Another important aspect of Grignard reagent is that refluxing is necessary to carry out the reaction (Weldegirma). The reagent has been studied for a very long time period. As early as the 1920’s, Grignard reagents could be identified and studied qualitatively by a color test. For a very…
Objective: The objective of this lab is to observe the synthesis of 1-bromobutane in an SN2 reaction, to see how a primary alky halide reacts with an alcohol.…
Under normal circumstances, room temperature, magnesium metal, Mg, reacts very slowly with the oxygen, O, in the air. However, as magnesium is heated, it reacts quicker with the oxygen and burns with a white light to produce MgO. To protect others from the smoke, containing Magnesium Oxide, the crucible had to remain covered. Some magnesium oxide escaped, when the crucible was not covered. The crucible had to be slightly ajar when heating up the magnesium, so that oxygen could get to the reaction. Without oxygen, a fire cannot exist. The shininess of the metal Mg turned to a dull appearance as it changed to MgO. As the magnesium reacted to the oxygen, it also reacted with the nitrogen in the air to form magnesium nitride, Mg3N2. To expel the nitrogen from the crucible, we added water to the mixture and heated it up. This would cause the Mg3N2, to react with the water, H2O, to form ammonia, NH3, and magnesium hydroxide, Mg(OH)2. The NH3 was driven off during the heating. One sign of this reaction was the ammonia smell given off. This is because upon heating, the Mg(OH)2 would break into MgO and H2O, which would be driven off by the heat. The second reheating was so that any remnants of the Mg(OH)2 of the crucible had been converted to MgO. This was also to have an accurate final mass of our product MgO. After the lab, the inside of the crucible was black. This is because the magnesium not only reacted with the oxygen and the nitrogen in the air but also with the porcelain of the crucible. The reason for waiting for the crucible to cool before weighing it was because at higher temperatures, the molecules inside are still active, causing the weight to be off. During Trial 2, the magnesium was not properly burned off and caused the calculations to be off. The magnesium looked as if it had stopped glowing, but the inside coil was not completely…
The carbon bonded to the metal is an excellent nucleophile and base. This carbon with carbanion character can partake in typical nucleophilic reactions such as nucleophilic substitution or carbonyl addition. The experiment performed is an example of carbonyl addition using a Grignard reagent.…
In the first reaction, magnesium was burned to produce magnesium oxide. The reaction produced a bright light, which is evidence of a chemical change. The second reaction occurred as a result of solid magnesium reacting with hydrochloric acid. The reaction produced heat and bubbles, both indications of a chemical change. A wood splint was used to determine that the gas produced was hydrogen gas, hence the other product is magnesium dichloride. In the third reaction, ammonium carbonate was heated to decompose into two gases, due to the absence of anything solid or liquid following the reaction. A wood splint was used to determine that carbon dioxide was present, since the lit splint was extinguished when put in the test tube. Therefore, the other product is ammonium oxide. The fourth reaction occurred between calcium carbonate and hydrochloric acid. When mixed, the two reactants produced a clear aqueous solution, calcium chloride, water, and a gas. The gas was concluded to be carbon dioxide, since the wood splint was extinguished after it was exposed to the gas in the test tube. In the fifth reaction, the two reactants, copper(II) chloride and zinc produced a permanent color change in the solid substance in the aqueous solution. The remaining solid appeared to be black reddish and concluded to be copper, where the aqueous solution is zinc chloride. The six reaction resulted in the formation of a precipitate in an aqueous solution. Copper(II) chloride reacted with sodium phosphate to produce a fluffy blue solid, copper(II)…
3. If the bromobenzene is added too quickly, what side product is formed (Draw the structure in pen and name it!)?…
One of the limitations was that the experiment required us to lift the lid of the crucible from time to time to check and see if the reaction was finished. When this was done, it was observed that some white smoke escaped. This was the product, Magnesium Oxide. Any escape of the product would bring about a different set of results.…
The purpose of this experiment is for one to be able to determine the standard enthalpy of formation of Magnesium Carbonate. Every chemical and physical change is accompanied by a change in energy, which usually occurs in the form of heat. The heat of a reaction, also referred to as the change in enthalpy, is denoted by the symbol H. The enthalpy of reaction is expressed as the heat quantity that is evolved or absorbed when one mole of the reactant is converted to product. This is considered to be exothermic…