Allow the mixture to cool for a few minutes then filter it, using either gravity or vacuum filtration. (We shall be using vacuum filtration.) Wash the residue in the funnel once with a little water and collect all the filtrate. 4. Pour all the filtrate and washings into a 250cm3 volumetric flask.
Add 1 mL of deionized water to the small test tube containing the precipitate and mix it and centrifuge it for 60 seconds. Then, add the supernatant into the boiling test tube and repeat this step one more time with another 1 mL of deionized water. Acquire a pair of metal test tube holders and heat the boiling test tube to evaporate the water for 15 minutes. Let is cool after and weigh it. Then, calculate a percent yield of zinc iodide and write a balanced chemical equation and determine the limiting
Using another 125-mL flask, 60-mL of 0.3622 M potassium hydroxide in ethanol was deposited. Both flasks were clamped in a temperature-controlled bath regulated at 50.0˚C. The solutions were then set in the temperature bath for ten minutes to equilibrate. An empty 250-mL Erlenmeyer flask was also clamped in the same water bath. In another flask 50-mL of ice water was deposited with three-drop phenolphthalein.
Procedure 1. Begin to prepare an EDTA solution. Weigh out 3.62-3.64 g of NaH2EDTA and record exact mass. Add the weighed amount to a 250 ml volumetric funnel carefully using a funnel Wash the funnel with water to ensure all of the solid is delivered to the flask Add 100-200 ml of water and mix. Enough water should be added so that the flask is full to the 250 ml mark Tightly wrap the top of the flask with a Parafilm when finished 2.
The seaweed will be cut and weighed (6 grams) and transferred into 150 mL solution. Using 40 mL of distilled water the seaweed is heated just under boiling for five minutes. After cooling, a filter will be used to remove the seaweed from the extract. The goal is to transfer 2-3 mL of filtrate into the evaporating dish. We now slowly pour the solution into a funnel with filter paper.
5mL of acidified water will be measured, using a graduated cylinder, and will be transferred to the R tube, and will be immediately vigrously mixed with the reactants. Once the solution turns to an orange or red-brown color, a pipet will be used to quickly remove 30 drops of the solution, then transferred to the C tube, and the mixing will resume until the solution is close to room temperature. The solution will be filtered into the P tube, and the solution that is left in the R tube should be washed three times with 1mL of acidified water each time. The water should then be poured into the P tube, leaving the solid in the R tube. Using a test tube holder, heat the R tube over the Bunsen burner, moving the tube in a circular motion until all the water has evaporated.
Dispose of solutions down the drain. Part II 1. Fill one 50ml beaker with tap water and add crushed ice to make an ice bath. 2. Fill one 50ml beaker with very hot tap water to make a hot bath.
The liquid of homogenate was filtered into a beaker through Miracloth (2 layers cloth) to remove large plant components and 1 ml of the filtrate was transferred to a conical tube. 8.4 g of ammonium sulfate was slowly added to the 40 ml of the filtrate as it was stirred on a stir plate for 15 min to achieve 37% saturation (210g/L of solution). The solution was then centrifuged at a speed of 9000 x g at 4oC for 15 min to sediment the proteins. The resultant supernatant 1 was transferred to a beaker with 1 ml transferred to a conical tube and the obtained pellet 1 was resuspended in 4 ml of distilled water and transferred into a dialysis bag to remove the salt. Then, 3.4 g of ammonium sulfate was slowly added to the supernatant 1 as it was stirred for 15 min to achieve 50% saturation (85g/L of solution).
Bring the contents of the distillation flask to a gentle reflux (i.e., vapors are condensing in the first ¼ to 1/3 of the vertical condenser and dripping constantly back into the flask below). Maintain this reflux for 10 minutes, then increase the heat in order to distill the liquid into the collection flask, then the column, and even the distillation head with aluminum foil (shiny side IN). Continue distillation of the cyclohexene product until the volume in the distillation flask is reduced to about 1 mL. Ask the instructor to assist you in removing the heat source and sand bath for the almost empty flask; use Ove Gloves and/or clamps to avoid burns. |
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.