In the first part, five 100 mL flasks of 5 mL ligand solution, 5 mL 2 M sodium acetate, 4 mL 3 M NH2OH, and 1-5 mL Fe2+ solution are diluted with water. The absorption spectrum for varying concentrations of Fe2+ are measured using a spectrophotometer and the data is graphed in Excel. The slope of the line is ε in the Beer-Lambart equation A = εcl. In the second part of the experiment, eleven flasks containing diluted stock solutions of Fe2+ and ligand are mixed with 5 mL 2 M sodium acetate and 4 mL 3 M NH2OH and diluted with water. The absorption spectrum is measured using a spectrophotometer and the data is graphed in Excel.
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 a measuring cylinder, add 50cm3 of 1.0mol dm-3 sulphuric(VI) acid to the thyme extract in the conical flask. 8. Titrate the solution in the conical flask with the potassium manganate(VII) solution until a pale pink colour persists for 10 seconds. 9. Repeat the titration until there are two titres within 0.1cm3 of each other.
Twenty drops of bromothymol blue was also added to the 150mL beaker. The pH was then obtained using the Vernier pH probe and it read 6.68. The 5mL pipet was then used to transfer 5mL of the green solution to the three 50 mL beakers. A 100mL beaker was obtained and filled with 1.0 M HCl solution and the pipet was used to acquire 1mL of the 1.0 M HCl solution. The 1mL of HCl was then transferred to one of the 50mL beakers turning the color of the solution to yellow.
c. Prepare the solution by dissolving 38.90 grams of ZnI2 with 500 mL of water. d. 0.0125/0.25 = 0.05 L = 50 mL. This produces 0.0125 moles of ZnI2 5. Exercise 5: a. (0.125)(0.1) = 0.0125 moles of solute b. Pour 50 mL of the stock solution to get the number of moles needed.
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). The supernatant was then centrifuged at 9000 x g and 40C for 15 min and 5 ml of the second supernatant was transferred to a conical tube. The obtained second pellet was resuspended in 4 ml of distilled water and transferred into another dialysis
2 mL of a saturated calcium acetate solution was added to an evaporating dish. 15 mL of ethanol was added to the dish and swirled. The dish was ignited. 8. 3g of NH4Cl and 7g of Sr (OH) 2 * 8H2O were added to a 125 Erlenmeyer flask and swirled vigorously for 5 minutes.
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.
The sample size was 100 termites and there were 5 replications for each level of treatment. The species being used was termites. The experiment was carried out by first gathering 100 termites into a glass bowl. Two equal sized circles were drawn with each writing utensil on a blank sheet of white paper. Figure 1 shows the circles that were drawn with a red ink pen and red ink sharpie marker.
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.