Allow the crystals to dry for 1 week then, weigh it, take a MP, and calculate the % yield. * Assemble the apparatus for reflux using the diagram (see figure 1), place boiling chips or a stirring bar in the bottom of the flask. * Weigh 2grams of finely ground nutmeg and combine with 10ml of diethyl ether in a 50ml round bottom flask. * Place a heating mantle under the round bottom, turned on and the heat was slowly adjusted until the mixture starts to boil for 45minutes, then let cool to room temperature by sitting it on the lab bench. * Pour a little ether over the nutmeg residue on the filter paper so that any Diethyl ethanol traces clinging to it is washed down and mixed with the filtered liquid underneath.
The solution in the beaker which was distilled water was clear before the IKI was added and before the dialysis tubing was placed in it. After the Benedict’s test the solution turned blue. Table 3: Solution Color After Sitting for 30 Minutes and After the Benedict’s test Solution Content | Color after 30 minutes in the beaker | After Benedict’s test | 15%
After a few minutes the acid dissolved the capsule creating a black foam that then turned into a clear liquid again. Once the liquid was clear again, the clamp was closed and the beaker was weighed. The temperature of the water was also taken. This was then repeated again for Trial 2 with a new capsule. Specialized Chemical Techniques: The specialized technique used in this experiment was
• After the flask was heated, I removed it from the heating mantel and allowed it to cool to room temperature. • Next, I poured 15mL of absolute ether and 9mL of bromobenzene into the 250mL flask and waited 5 minutes for any reaction. • There were no signs of reaction after 5 minutes; therefore the lab assistant used a glass stirring rod to crush the magnesium in order to get the reaction started. When this was done, the liquid became cloudy, rapidly bubbling, and the color turned rusty red. • Next, I added 25mL of absolute ether and attached a reflux condenser to the flask.
B. Tollens Reagent. Prodedure: 1. Number 4 clean 10-cm test tubes 1,2,3, and 4. 2. Put 15 drops of dilute (6 M) sodium hydroxide (NaOH), into each test tube and allow them to stand for at least 1 minute.
First I made a water bath by filling the 100 mL beaker with cool tap water. I then placed crushed ice in the 100 mL beaker so the water level was just below the top of the beaker. I sprinkled a little salt in the ice water and mixed it well. I then filled the test tube half full with distilled water and set the test tube in the 24 well plate. I inserted the digital thermometer into the test tube and took reading every 30 seconds until the readings remained constant.
E. coli has even been used to synthesize human insulin. Other strains are pathogenic, causing diarrhea, urinary tract infection and even fatal illness. Unlike some bacteria, E. coli cannot tolerate harsh environments, and instead thrive at 37°C. The primary goal of this experiment is to examine the growth of E. coli on bacterial lawns in order to determine expired mouthwash’s efficiency as an antibacterial product. Since it is expired, the mouthwash should not perform well as an antibacterial agent.
We weighed the resulting powder to be 3.228 grams. We then transferred the powder nutmeg into a 50 ml round bottom flask and added 15 ml of dichloromethane. We placed our flask in to a standard heat reflux apparatus and gently refluxed the mixture. We waited until we saw the first drip of liquid in the apparatus and heated for 15 minutes. After the mixture was heated, there was solid on the bottom and liquid on the top of the flask.
25 ml of diluted unknown acid solution to 100ml beaker by using 25 volumetric pipet. 10ml of deionized water and 3 drops of phenlpthalin indicator the beaker labeled as 3. Potentiometric titration acid solutions 125 ml of NaOH was obtaining in a beaker and 50 ml of NaOH transfer to buret the tip and the meniscus is at below 0 ml. one magnetic stirring bar placed in a beaker contain one of the known solution on a stir. The pH recorded by using pH electrode before adding NaOH.
Title: The effect of concentrations of water and sucrose solutions in dialysis tubes on the diffusion of water of each tube as measured by scales weighing each tube and comparing it to its starting weight under the conditions of ten minute intervals, five milliliters of each solute and beakers filled with the same amount of solution. Abstract: This osmosis lab was done to show how water moves from high to low concentrations across a selectively permeable membrane. Four dialysis tubes were used in the experiment, one tube filled with 5 mL of tap water, the second filled with 5mL of 20% sucrose solution, the third filled with 5mL of 60% sucrose solution, and the fourth filled with 5mL of tap water. All the tubes were weighed initially, and then submerged into beakers. The first three were submerged in tap water-filled beakers, and the fourth tube was submerged in a beaker filled with 60% sucrose solution.