Using Buffers. Jason Blot. 02/26/2017. . Purpose:. . The

Again, label 7 1.5ml tubes 0 thru 6. Place 15μl of each serially diluted extract into its corresponding labeled tube. Next add 465μl of media into each tube. Then 60μl of Alamar blue in each tube. Finally add an additional 60μl of cells (adjusted to 10,000 cells/20 μl). Vortex each tube for 5 seconds. Now, take 3 different samples 190μl samples of concentration 0 and put it in Wells A2, B2, and C2. Repeat this step again by taking 3 more different 190μl samples of concentration 1 and putting it in wells A3, B3, C3. It should be noted that it is important to vortex each 1.5μl tube again be-fore putting it into the 96 well plate. Contin-ue this same procedure consecutively for the re-maining concentrations.

1.) Measure out 20ml out of the water and place it into a glass beaker

1. Describe the graph of pH values over the course of the reaction in Part II. Was the change in pH consistent over the course of the reaction? Do your best to explain the reason for the shape of the pH curve in your own words:

Table 1: This table shows the position that the solution was at inside the graduated tube it was held in at each time interval it was measured.

In 2 and 7 I added 50 mL of .1 M NaCl. I added sodium acetate to the rest of the beakers: 1 gram to 3 and 8, 5 grams to 4 and 9, and 10 grams to 5 and 10. I then filled the beakers that contained the solid sodium acetate with 50 ml of .10 M acetic acid. Specifics can be found on page 84 of the lab manual. Though the lab manual instructed to use a pipet, we did not have an accurate 1 mL pipet or a graduated pipet, so we instead prepared two graduated burets with 1 M Sodium Hydroxide and 1 M hydrochloric acid. Using a standardized pH probe with a Lab Pro to measure changes in pH, we added 1 mL of HCl at a time and recorded the changes. The same was done for the NaOH.

3. We poured tube 1 with the solution in tube 3 to combine them. We repeated this for all of the tubes. Each of the tubes in step 1 was mixed with a tube in step 3, making there be 6 total test tubes with a solution in it.

weak bases). After ranking the pH of these solutions, you will then test your predictions in the laboratory.

Gather the following lab equipment: Goggles, test tubes, 24 well plate, Gas assembly with copper and plastic tubing and a #00 stopper, short stem pipet, rubber stopper #00 with one hole and a pipet tip with plastic gas delivery tube, 2 small tables of AlkaSeltzer, 4mL Bromothymol blue .04%, 20 mL hydrochloric acid, 4-6 pieces of manganese metal, 4-6 pieces of mossy zinc, and 3 pipet bulbs.

3. Add a drop of enzyme solution to only one of the wells. The other well without enzyme added to it will be your control.

After that, both spouts were closed and the burets were filled with the solution being used to around the zero mark. Some solution had to flow out in order for there to be no air bubbles at the tip of the burets. The burets were then labeled acid or base to fit their corresponding solutions. To start the titration, the initial values of the burets were recorded in the data table. A known volume, 10 mL, of HCl was delivered to the Erlenmeyer flask, and a few drops of the indicator, phenolphthalein, were added also. In the first trial, 3 drops of this was used. Then, the spout of the buret containing the NaOH solution was opened, and the chemical was added to the flask. While the NaOH was mixing with the other solutions, the flask was constantly being swirled. As the color changed briefly and returned to normal, the flow of the NaOH was slowed down. By adjusting the spout of the buret, the flow was drop by drop. If the color became too bright pink, single drops of HCl were supplied to the solution to get it to a faint pink color. The endpoint was determined by swirling the flask for at least a minute, and seeing if the color stayed while viewing it on top of a white piece of paper so the color was more

After the solution turns yellow or is neutral on a PH strip record the ending point and figure out how many mL of HCL it took to titrate the solution. Do this three times and take the

The method I used in the experiment was followed by the lab manual of “Fundamentals of Life Science by Brenda Leady” (Leady 2017). We conducted an experiment of 8 different tests, 4 of the different classifications of pH, and 4 different

2. Following solutions are added to the tubes and the pH of each tube is determined:

d. Add one drop of I2KI solution to each of the wells and record your result in the table below. Table 2. Iodine Test Results

Table 2: Consists of color extract taken from a red cabbage for a natural indicator. The pH reading that was measured by using the pH meter and the result of the pH reading to determine whether the solution was acidic or basic.