Evaluation Of A Module 11 Analysis

Vial number one had trouble staying down but my group held it under until finally they were able to get it to stay underneath the water. The rubber band could now be removed from the tray. The respirometers were in the water for a timed three minutes to allow them to equilibrate. After the three minutes was up the initial level of oxygen that entered the pipet was recorded in our lab books. After this data was found and recorded we were finally able to begin the actual experiment testing.

A 0.5 g of sodium tungstate dihydrate was weighed and transferred into a 50-mL round-bottom flask with a magnetic stir bar. Approximately 0.6mL of Aliquat 336 was then transferred carefully into the round bottom flask using a 1mL syringe. The round bottom flask and its contents were then set up in an oil bath. 11mL of 30% hydrogen peroxide and 0.37 g of potassium bisulphate were added to the reaction mixture in the round bottom flask and stirred using a magnetic stirrer. Lastly, 2.5mL of cyclohexene was added using automatic dispenser and the mixture stirred. A condenser was fitted on the round bottom flask, clamped and attached to water horses. The reaction mixture was then heated on the oil bath and the reflux process initiated for an hour while stirring the mixture vigorously. Half way while rinsing, any trapped cyclohexene in the condenser was rinsed. After 1 hour, the round bottom flask was rinsed

PH sensors are used in many scientific laboratories to measure the hydrogen-ion concentration of a liquid substance and to determine the basicity and acidity of a liquid. PH meters measure the electrical potential difference between a reference electrode probe and a pH electrode probe. Since these probes are very sensitive, they are required to be kept cleansed from contaminants. If exposed to contamination, one risks faulty or unreliable data, since their accuracy is dependent on a regular calibration and upkeep. To avoid this risk, and accurately measure hydrogen-ion concentration, the probes are kept in a buffer solution and calibrated before each use. [1]

3.0g of salicylic acid was weighed then 3.0mL of acetic anhydride and 6 drops of 85% H3PO4 were added to it. The mixture was warmed over a water bath for 5 minutes while stirring. After warming, 20 drops of distilled water was slowly added. 15mL of water was added then the solution was heated until it became clear. It was allowed to cool and was placed in an ice bath until the solution becomes cloudy. Using pre-weighed filter paper, the mixture was filtered and was allowed to dry in the filter paper.

The experiment first started by the calculation of the net oxygen production under white light, it started by putting the Elodea in a volumeter tube containing 3% sodium bicarbonate solution, which was assembled to the volumeter by covering the tube with the plug/pipet/syringe assembly (a 1-2cm air space between the bicarbonate solution and the top rubber cover of the volumeter tube should be left.) Then, clamp the volumeter onto the clamp stand using the tube clamp and fill 2000ml beaker with cold tap water. The beaker should be placed on the clamp stand between the volumeter tube and the light lamp. A five minutes stabilization

1.5mL of phosphoric acid including 3-4 boiling chips were also added to the 25mL flask. The short path distillation apparatus was set up as shown in Figure 1. A heating mantle was used to heat up the 25mL flask. The solution was distilled to the receiving flask until a small amount of liquid remained in the initial RBF flask. At this point the presence of thick grey smoke pulling over into the entire apparatus was observed. The apparatus was then left to cool down. Through the use of pasture pipette, the aqueous layer from the distilled solution was drawn out. Sodium carbonate was then added to the remaining organic solution in order to check the pH and to verify the basicity of the solution. The aqueous layer was again drawn out from the solution. Next, 0.5g of sodium sulfate was added to the remaining organic layer and was swirled until the liquid appeared to be dry and clear. The alkenes were transferred into a clean 10mL flaks using another clean pasture pipe. The apparatus from the first distillation was rinsed off with

Three grams of a mixture containing Benzoic Acid and Naphthalene was obtained and placed in 100 ml beaker and added 30 ml of ethyl acetate for dissolving the mixture. A small amount (1-2 drops) of this mixture was separated into a test tube. This test tube was covered and labelled as “M” (mixture). This was set to the side and used the following week for the second part of lab. The content in the beaker was then transferred into separatory funnel. 10 ml of 1 M NaOH added to the content and placed the stopper in the funnel. In the hood separatory funnel was gently shaken for approximately one minute and vent the air out for five seconds. We repeated the same process in the same manner one more time by adding 10ml of 1M NaOH.

The materials needed for this experiment included test tubes, a test tube holder, the unknown compound #202, 35mL beakers, gloves, safety goggles, ethanol (to clean equipment), stirrer (to mix solutions), the 15 possible compounds that are provided, pH strips, distilled water, wooden splints, spatula to get out unknown compound #202, waste bucket, Bunsen burner, graduated cylinder, 500mL beaker for the waste, plastic dishes to measure out compound and the scale.

PH sensors are used in many scientific laboratories to measure the hydrogen-ion concentration of a liquid substance and to determine the basicity and acidity of a liquid. PH meters measure the electrical potential difference between a reference electrode probe and a pH electrode probe. Since these probes are very sensitive, they are required to be kept cleansed from contaminants. If exposed to contamination, one risks faulty or unreliable data, since their accuracy is dependent on a regular calibration and upkeep. To avoid this risk, and accurately measure hydrogen-ion concentration, the probes are kept in a buffer solution and calibrated before each use. [1]

To begin, three sets ofabout 0.3000g of KHP are weighed out on an analytical balance. Put the three sets of KHP into three separate, labeled flasks. All three sets of the KHP is then dissolved with approximately 50mL of deionized water. Next, a buret is used to start the actual titration. Buret is initially filled to 0.00mL mark with the NaOH solution, this is recorded as initial volume. Next, add 2-3 drops of phenolphthalein indicator into each of the three flasks containing KHP. A magnetic stir bar is then added to the first flask, and placed above a stir plate. Everything is positioned under the buret. Stirrer is put on medium speed and the titration can start. Slowly release the NaOH into the KHP flask. As the end point is reached, a pink color will be seen in the flask. When the lightest pink possible remains in the solution for more than 30 seconds titration is complete. The final volume is recorded, and the same steps are taken for the other two sets of KHP solution. Finally, blank titration is completed to determine deviation.

Subsequently, HCl was added, drop-wise, to the labeled NaHCO3 extract. Once the solution had a pH of 2, additional HCl was not needed: 3-chlorobenzoic acid was precipitated. An ice-water bath beaker (250 mL) was made to cool the acidified solution. Eventually, a Buchner filtration apparatus was assembled with a pre-weighed filter paper; not to mention, wetted in the apparatus. Then the apparatus was attached to a water aspirator and the water valve was opened.

After calculating the pH and measuring the pH, the data indicated that there was experimar error (see Tables 2, 3, 4, and

In 2.1.1 and 2.1.2, the molarity of solution X is 0.1 M theoretically but after the preparation and calculation, we got 0.083 M. This might occur due to transfer the concentrate HCL into the conical flask excessively as we have to do it in the fume cupboard. Besides, pouring the distilled water more than the line also another factor. There are some precautions that must be follow during using fume cupboard such as the fume cupboard must place away from windows or doors and keep a distance from the fume while perform the work (Dugan,2013). Borax or known as disodium tetraborate was used as a base because it is solid (Sanjeetmanna, 2012) that can be measured easily, odourless, and colourless crystalline that forms from boric acid. Borax insoluble in cold water because cold water can hold less borax than hot water. When it completely dissolved in hot water and reached its saturation point, supersaturation occurred as it cannot

An ice bath was prepared in a large beaker and a small cotton ball was obtained. 0.5 g of acetanilide, 0.9 g of NaBr, 3mL of ethanol and 2.5 mL acetic acid was measured and gathered into 50mL beakers. In a fume hood, the measured amounts of acetanilide, NaBr, ethanol and acetic acid were mixed in a 25mL Erlenmeyer flask with a stir bar. The flask was plugged with the cotton ball and placed in an ice bath on top of a stir plate. The stir feature was turned on a medium speed. 7mL of bleach was obtained and was slowly added to the stirring flask in the ice bath. Once all the bleach was added, stirring continued for another 2 minutes and then the flask was removed from the ice bath and left to warm up to room temperature. 0.8mL of saturated sodium thiosulfate solution and 0.5mL of NaOH solution were collected in small beakers. The two solutions were added to the flask at room temperature. The flask was gently stirred. Vacuum filtration was used to remove the crude product. The product was weighed and a melting point was taken. The crude product was placed into a clean 25mL Erlenmeyer flask. A large beaker with 50/50 ethanol/water

Subsequently, 10mL of 3.5% H2O2 were added dropwise to the reaction mixture and was stirred for 20 minutes before heating to boiling at 80°C for 5 minutes. The reaction mixture was then taken off heat and allowed to cool undisturbed in an ice-bath for 30 minutes. Suction filtration was performed after to collect the crystals from the chilled solution The product was then washed with chilled 95% ethanol (2 x 15mL) and followed by diethyl ether (2 x 10mL). The crude product was then left to dry before recording the yield. 20mg of the crude product is then accurately weighed out and dissolved in deionized water in a 25mL volumetric flask. Deionized water was added to the volumetric flask to the mark and the UV-vis absorption spectrum of the crude product was recorded.