After that, dissolve the sample in 2 mL of deionized water and shake the test tube for 1 to 1 ½ minutes to dissolve the solid. Place another dry test tube in a 50mL beaker and weigh it. Find a bottle of barium iodide and record the name and molar mass. Then, weight out either anhydrous barium iodide or barium iodide dehydrate into this test tube and dissolve is it in 2 mL of deionized water. Pour the contents of one of the test tubes into the other and a reaction should occur and you should see a white precipitate of barium sulfate form.
For every 20 drops of solution you will add 0.1g of zinc to the new test tube. Repeat steps 3 and four until the solution is clear. If there ever exists too little of the solution to get enough drops, add up to 1mL of distilled water to the solution. 4. Once the solution is clear, retrieve at least ten drops of the solution and place them in a new test tube.
Put a few iron filings back into the 100 mL beaker. 17. One lab partner should take the magnet to the back table and put the iron filings into the blue tray. 18. The other lab partner should add the 20 mL water to the 100 mL beaker and stir for one minute.
Procedure: 1. Fill a beaker two-thirds full of water and add approximately 20 drops of IKI. Write down the solution's color and record the mass of the bag. 2. Do an initial Benedict's test on the 15% glucose/1% starch and the beaker solutions for glucose by putting some of the solution and a roughly equal amount of blue Benedict's solution in a test tube, placing the test tube in boiling water for 90 seconds, and observing whether or not the solution changes color from blue.
Put exactly 5.0 mL of water in the 10.0 mL graduated cylinder. Record this volume in your data table (10.0 mL). Label the first pipet "Acid." To calibrate the pipet, fill it with LIU-2 water. Holding the pipet vertically, add 20 drops of water to the cylinder.
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.
Hydrate Lab The purpose of this lab is to analyze the percent water in a crystalline hydrate and to indentify the hydrate from a list of possible unknowns. The solid hydrate will be heated to remove the water, and the percent can be found by measuring the mass of the solid before and after heating. The hydrate will be indentified by comparing the percent water in the hydrate with the percent water calculated for the possible unknown. Before the lab there are pre-lab questions: 1. Describe the three general safety rules for working with a Bunsen burner.
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).
Transfer the distillate via Pasteur pipet into a 15-mL centrifuge tube. Wash the distillate with two 2.5-mL portions of water, removing and setting aside the water layer at each step. Transfer the organic material to a small, dry Erlenmeyer flask, leaving behind the last drops of the water layer. Remove any drops of water that were accidentally transferred to the Erlenmeyer flask, if any, then add small amounts of anhydrous sodium sulfate as drying reagent. When the liquid is dry, it will be transparent and some of the drying agent will flow freely like beach sand.
The supernatant was transferred to a 1.5 ml tube; to which 225 µl of 5 M NH4Ac was added, mixed gently, incubated on ice for 30 min and centrifuged at 10,000 rpm for 15 min at 4°C. Then the supernatant was transferred to a fresh tube, 510 µl of isopropanol was added to precipitate the DNA and centrifuged immediately for 10 min at 10,000 rpm. The supernatant was removed; the pellet was washed twice with cold 70% ethanol, air-dried and suspended in 50 µl TE