In this step, as we watched the chemical reaction with the solids, we noticed a thinning in the substance. Also, the solids became lighter and moved to the top. When stirred, the solution began to turn green and then back to light blue, where copper began in the end of the first step. A combination reaction took place, and the balanced equation is: CuOs+H2SO4aq→CuSO4aq+H2O(I) Following this step, step 5 began, in which we added 300 mg of zinc to the solution. Once the zinc was added slowly to the solution, a gas was released and the solution began to change colors.
Compare the MPs of the once recrystallized and the twice recrystallized trimyristin. After the hydrolysis has proceeded for 45 minutes, allow the flask to cool to RT and pour the contents into a 50 mL beaker containing 8 mL of water. Carefully, in the hood, add dropwise with stirring, 2 mL of concentrated HCl (caution: corrosive liquid/noxious vapors). Myristic acid should precipitate. Cool the beaker in ice water for 10 min, with stirring, and collect the solid by vacuum filtration on a small Hirsch funnel.
While stirring, 6 M NaOH was added drop-wise until the solution became basic, turning red litmus paper blue. A total of 3.84 mL NaOH was required to achieve this; the resulting solution appearing dark blue with cloudy precipitates. The solution was then heated gently atop a hot plate to catalyze the next reaction, with care taken to assure all residue was kept off the walls of the beaker. Heating continued until the reaction reached completion and the solution slowly changed from blue to a dark green and finally black. At this point the heat was turned off to allow the black solid in the beaker, CuO, to settle to the bottom.
The Loss and then Retrieval of Copper through Multiple Reactions Lab Partners: Justin Dunn and Alexis Almaguer Experiment #2 Section: 506 Intro: All science occurs within rules. One very important rule is that matter can neither be created nor destroyed and this rule will be expressed and proven in this lab by removing copper and then regaining it through multiple reactions, heating, and stirring. This experiment allows the students to learn the different types of reactions as well as learn new techniques within the laboratory such as vacuum filtration and handling hot glassware, but most importantly proves the law of conservation of mass. Materials and Methods: to begin the experiment a 50 ml beaker, hot plate, plastic funnel, aspirator,
4) Ignoring step 3, after step 2, you can take the solution that you have created and pour it into a 100 mL beaker. Once the solution is in the beaker, turn on the conductivity tester and gently place it in the solution (try not to touch the bottom of the beaker). Record the results. 5) Now, take the beaker with the solution already inside and place it on a hot plate. Turn on the hot plate to a medium heat.
2. In order to eliminate any air trapped in the jet, the hydrochloric acid was allowed to run out and the burette was refilled to above the zero mark. 3. The tap of the burette was then opened to allow the acid to run out until the bottom of the meniscus was just on the zero mark when viewed at eye level. 4.
Part B: A similar experiment was performed after the 15% NaI in acetone solution. This time, ten test tubes were marked and we put 2 mL of 1% ethanolic silver nitrate in each test tube. The same corresponding halide was added to the mixtures as the first part of the experiment. Once these halides were added, we observed to see which turned cloudy. The mixtures that didn’t turn cloudy were put into a hot water bath of about 100 C for about a min.
The mass was recorded and transferred to a 50 ml beaker. 4 ml of 6 M HNO3 was added to the beaker containing the copper. For step 2, 10 ml of distilled water was added to the beaker. Then, 6 M NaOH was added to the solution (drop wise), until placing a drop of the solution on red litmus paper turned it blue. For step 3, the solution was heated with a hot plate.
The watch glass was removed with the beaker tongs. Using a rubber bulb and a stirring rod to stir the solution continuously, 15.00mL of .25M BaCl2 solution was added to the solution in the beaker. The watch glass is replaced and the solution is keep hot but not boiling for 15 minutes. The precipitate was allowed to settle. When the liquid above the precipitate was clear, the solution was tested for completeness of precipitation when a few drops of BaCl2 solution were added from a pipette.
DO NOT LOOK DIRECTLY AT THE BURNING MAGNESIUM; THE INTENSE LIGHT CAN HURT YOUR EYES. The magnesium mass was calculated from the data in the lab table during the heating process. The reaction was complete when the gray powder was formed. Tongs were used to carefully remove the reaction off of the wire gauze to cool for five minutes. Two drops of water were added to the cooled crucible.