* Allow crystals to dry. * Weigh and calculate % recovery. Isolation of p-nitroaniline * Wash remaining organic layer with 5ml deionized water and extract aqueous layer into a beaker. * Add 10 ml of HCl to the remaining organic layer, shake , and separate the bottom aqueous layer. Repeat this step twice.
II. Procedure Use a 10-mL graduated cylinder to put 6mL of 6 M sodium hydroxide solution (NaOH) into a clean 500mL storage bottle. Use a 100mL graduated cylinder to add 345mL of distilled water to the plastic bottle. Place a lid on the bottle and mix by shaking repeatedly. Sit the bottle off to the side for later use.
Then by writing a balanced chemical equation and using the titration formula, Nb+Ma+Va=Na+MbVb , the molarity is able to be determined. Procedure: 1) Using the graduated cylinder add 10.0 mL of water into the Erlenmeyer flask. 2) Add 5.0 mL of HCl into the flask using another graduated cylinder because acid goes into water when mixing them. 3) Add three drops of phenolphthalein indicator into the flask. 4) Swirl the flask in circular movements to mix the substances.
Reaction II For the second reaction, we need 25 mL of 0.005 M lead nitrate and a clean 50 mL graduated cylinder. Add 1.4 mL of 0.25 M potassium iodide (we used 30 drops) into the flask. Pour the solution into the vacuum flask. Decant the solution evenly into two beakers. For the first beaker, we add 1 mL of 0.1 M potassium phosphate.
Make sure that none of the tubes have been contaminated with acetone (which gives a positive DNP test) in the cleaning process. 3. Put 10 drops of DNP reagent into each of the four test tubes. **Safety alert**The DNP reagent should be handled carefully and kept off skin and clothing. If contact occurs, wash the contacted area immediately with cool water.
Next, obtain a 5 mL serological pipet and thoroughly rinse it with the buffer solution, then discard the buffer solution into the 250 mL beaker. Now, use the pipet to distribute 5 mL of the buffer solution into three 50 mL beakers. Be sure that the 50 mL beakers have been cleaned are dried prior to this. Next, locate the three pre filled burets in the lab room. Find the buret labeled 1.0M HCl and add exactly 1.00 mL of HCl to just one of the three 50 mL beakers with buffer solution already in them.
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.
Repeat this two more times 5. Use a pipet to put 10 ml of the appropriate solutions in each bag: Bag 1: 10 ml – 10% sucrose Bag 2: 10 ml – Distilled Water Bag 3: 10 ml – 10% Sucrose 6. Squeeze as much air as possible out of the tubes and tie the remanding open sides shut. 7. Make sure to cut the excess string hanging off of each bag.
Drops from the column were collected from this point on, using 10 collection tubes labeled 1-10. Each tube was used to collect approximately 5 drops of solution from the column in ascending numerical order. 25 microliters of the buffer solution were consistently being added to the column to prevent the column from drying. The 5 drops of solution in each of the clear collection tubes provides a way to observe the color saturation of the separated molecules. Two visible gradients of reddish brown (collection tubes 1-4) and pinkish red (collection tubes 6-9) were collected.
In the first part, five 100 mL flasks of 5 mL ligand solution, 5 mL 2 M sodium acetate, 4 mL 3 M NH2OH, and 1-5 mL Fe2+ solution are diluted with water. The absorption spectrum for varying concentrations of Fe2+ are measured using a spectrophotometer and the data is graphed in Excel. The slope of the line is ε in the Beer-Lambart equation A = εcl. In the second part of the experiment, eleven flasks containing diluted stock solutions of Fe2+ and ligand are mixed with 5 mL 2 M sodium acetate and 4 mL 3 M NH2OH and diluted with water. The absorption spectrum is measured using a spectrophotometer and the data is graphed in Excel.