Add another 20 mL water to the 100 mL beaker and stir for one minute. (40 mL total water in beaker) 21. Make observations. 22. Fill out Dissolve Column and Floats Column on Data Sheet.
A cuvette block, four cuvettes, three 50 mL beakers, one 150 mL beaker, and one 5mL pipet were obtained. The phosphate buffers NaH₂PO₄ and Na₂HPO₄ were procured weighing .4060g and .4106g respectively. The phosphate buffers were then transported to the 150mL beaker. Next 50mL of distilled water was measured using a graduated cylinder and added to the 150mL beaker. Twenty drops of bromothymol blue was also added to the 150mL beaker.
* 3. 3.0 ppm standard: * 3.00 mL of 10.0 ppm phosphate solution was placed in a 25 mL graduated cylinder and diluted to exactly the 10 mL mark with distilled water then poured into a plastic cup labeled 3. Cylinder was rinsed with distilled water. * * 4. Zero standard: 10 mL of distilled water was poured into a plastic cup labeled 0.
Mix. k. Measure out 3/4 cup of the solution from cup 3 and add it to cup 4. Mix. l. What are the relative salt concentrations of cups 1–4? Example: Cup 2 is made up of half stock solution and half tap water, which is a 50 percent relative salt concentration.
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.
Materials and Methods To begin, .4001 grams of Na2HPO4 and .4081 grams of NaH2PO4 solid was added together into a clean, dry 150 mL glass beaker. Then, approximately 50 mL of distilled water was added to the mixture, and the phosphate solids were stirred until fully dissolved. The last ingredient added to the beaker was exactly 20 drops of the liquid .04% bromothymol blue solution. Using the Vernier pH probe, the initial pH of this soluton was found to be 7.10. After obtaining three clean, dry 50mL glass beakers (Labeled one of each “yellow,” “blue,” and “green.”) approximately 5.00 mL of the solution from the 150mL beaker was added to all three with a volumetric pipet.
Next, 50 mL of distilled was placed into the 150 mL. Twenty drops of Bromothymol blue were added to the 150 mL beaker solution. The pH was then recorded. Five mL of this solution was transferred into three separate 100 mL beakers. In one of these beakers, 1 mL of HCl was added to the solution, making this the “Yellow” beaker.
Add 0.1M HCl one drop at a time. Use the stirring stick and stir each time a drop has been added. Determine the pH after 5 drops have been added. Repeat the procedure until 30 drops have been added. 4.
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
Add water to your graduated cylinder until you have exactly 50ml (this is your volume). 3. Find the weight of the water plus the cylinder and record in your data table. 4. Find the weight of only the water by subtraction.