Results and Discussion For the first part of the experiment (Part A), five different 100 mL volumetric flasks were each filled with 1,2,3,4 and 5 mL of iron (II) solution. Then 5 mL of YY ligand, were poured to each of the five flasks. Each flask had 5 mL of 2M sodium acetate and 4 mL of 3M NH2OH. Then the whole solution was diluted up to the 100 mL fill mark with distilled water. This was the solution that was used in order to obtain the absorption spectrum for each of the different iron (II) ligand examples different flasks.
Measure the solution by right clicking on the beaker and choose pH meter *Then I had to measure the pH of 0.1 M sodium hydroxide Get a 100 mL beaker from the equipment menu Right click on the beaker, select chemicals, and add 50 mL of 0.1 M sodium hydroxide. Measure the solution by right clicking on the beaker and choose pH meter Part 2: *First add 35 ml of unknown acid a to 100 mL beaker. Select all chemicals from the toolbar in the chemicals section, choose unknown acid a. Put the volume at 35 mL in a new 100 mL beaker. *Then add two drops of phenolphthalein indicator to the beaker by right clicking, choosing indications, and adding 2 drops of phenolphthalein.
Then 5mL of HCl was added to copper to completely remove all traces of zinc. Once the bubbling had stopped, the rest of the liquid was decanted away from the copper. Then the copper recovery set up was put together using tubing, Buchner funnel, filter paper and suction flask. Then the filter paper was weighed before placing it in the funnel and wetted down. The aspirator was turned to medium high, and then the copper was poured onto wetted filter paper.
Chem 131A: pH and Buffers Experiment This experiment is designed to review your background in pH and buffers and to expand upon it. The first section involves the titration of an unknown amino acid through its two equivalence points. The equivalence point data will allow you to determine apparent pK values which you will correct for ionic strength and the molar mass of your unknown. Further, you will examine how the amounts of the major species change along the titration. The second section examines the effect of ionic strength on the pK of a weak acid.
Approximately 20 drops of a .04% Bromothymol blue solution was then added to the beaker of the phosphate buffer. Using a clean 5 mL serological pipette, transfer 5 mL of the phosphate buffer and Bromothymol blue solution to each of three clean 150 mL beakers. Next, using the buret for HCl, add 1 mL of HCl to one of the three beakers, then label this beaker “Yellow”. Next use the buret for NaOH and add 1 mL of NaOH to another of the three beakers, and label this beaker “Blue”. Lastly add 1 mL of water using the buret for water to the last beaker, and label this beaker “Green”.
The buret had used the NaOH thoroughly rinsed three times because at the first titration the NaOH solution was used. About 50Ml the NaOH solution was in a clean beaker and brought it to experiment area. A funnel was used to fill the NaOH into the buret and recorded the initial volume on the buret to the correct number of significant figures. A pipette was used to take 10.00ml HCl into a clean 50mL Erlenmeyer flask. Three drops of phenolphthalein indicator was added into the HCl solution.
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. 3. Form a bag out of dialysis tubing by tying off one end, putting in enough 15% glucose/1% starch solution to fill it halfway, and tying off the other end leaving the other half of the bag void of anything (even air). Write down the solution's color. 4.
* 5ml of distilled water was poured down the sides of the beaker, swirled and poured into the funnel. * The filter paper containing the precipitate was allowed to dry and then weighed. 1.7g/1.4g * The weight of the filter paper was subtracted (1.1g/0.7g) to give the actual yield of calcium carbonate (0.6g/0.7g). Observations: * When CaCl2 and Na2CO3 were mixed, a white precipitate was noted immediately. * Residual precipitate was observed on the beaker when filtering.
Wait 90 seconds for the light source to warm up, then fill a cuvette with distilled water and clean the flat, clear sides on the cuvette with a Kimwipe, removing dust and fingerprints before putting the cuvette into the instrument. Orient the cuvette so that the clear sides line up with the white arrow on the top of the spectrometer. Click “Finish Calibration”, then “OK”. Next, fill a cuvette with the “yellow” sample, repeating the steps to clean the clear sides of the cuvette with a Kimwipe to remove fingerprints and dust. Place the clean cuvette containing the “yellow” sample into the spectrometer, orienting the cuvette so that the clear sides of the cuvette line up with the white arrow in the cuvette.
When the liquid above the precipitate was clear, the solution was tested for completeness of precipitation when a few drops of BaCl2 solution were added from a pipette. Next, filter paper was place into the funnel and streamed with distilled water. A clean 400mL beaker is placed under the funnel and the precipitate was filtered through. When all the precipitate was filtered and removed from the beaker the residue is washed with distilled water. About 3mL of the wash water is collected in a small test tube.