The purpose of this experiment we will learn about components of a chemical buffer. We will also be able to define terms like buffer, buffer range, and buffer capacity after this experiment.
We will observe the reaction of a buffer solution with added acids or bases. We will then evaluate buffering capacity in response to additions added from dilute acid and bases to the buffer.
Procedure & Material :
•Bottle of water
•Box of toothpicks
•Pair of scissors
•Roll of paper towels
•Two graduated pipets
•Pair of gloves
•pH test strips
•Short stem pipet
•Test Tube cleaning brush
•24 well plate …show more content…
13. Dip the end of the ph Strip into well A1 to get the ph value and label in Data Table 1.
14. Using the well D1 pipet, add two drops of the HCI to the well A1 buffer.Use a toothpick to stir the solution.
15. Now again using another pH strip, dip the end to get an calculated pH level for the new solution and record in Table1.
16. Repeat steps 12-15 seven more additional times, each time adding 0. M of the HCI to well A1. Put all data into Table 1.
17. Now that we did well A1, let 's use well A6. First take a measurement of the pH solution and record it in Table 2.
18. Use the pipet labeled with well D6 and add two drops of the NaOH into te buffer in well A6.
19. Stir the solution with a toothpick and observe any changes. Measure the pH of the new solution and record into Table 2.
20. Repeat steps 17-20 seven more times similar to the other solution and record all data and changes in Table2.
21. Now , measure the starting pH level of the B1 well and record it in Table 3.
22. Take the pipet and add 2 drops of HCI directly into the well B1. Stir with a toothpick to mix the solution and observe any changes.
23. Measure the pH with a pH strip and record the data of the new solution in Table 3.
24. Repeat steps 22-23 four more times adding addition HCI each time to well B1. Record all data in Table 3.
25. Lastly, measure the pH of the solution in well B6 and record this initial
Buffers can be used to resist change in pH in an acid or base solution. The purpose of the lab is to understand the properties of buffers in relative concentrations, in the presence of a strong acid/base and dilution of buffer components the ammonia/ammonium buffer system. In this case, these laboratory techniques associated with buffers are performed to determine the pH values in diluted solutions. This is done by observing the Henderson-Hasselbalch equation. This represents the pH value by comparing the p value and the concentrations of a weak acid and conjugate base of a buffer solution, as long as assumptions are valid. From there, a pH vs log can be used from the values obtained. Then, the theoretical pH of solutions can be determined with the addition of a strong acid (HCl) and base (NaOH). From this, the effect of dilution can be viewed when plotting the calculated pH values vs dilution on the same graph.
The first step that needed to be done in this experiment was adding hydrochloric acid (HCl)
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.
twice. Place the pH probe in the beaker and record the pH in the data table. Drag the beaker to the red
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.
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:
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.
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.
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.
Next, select the test tubes and put it on the test tube rack; and, wash all the glassware with distilled water. Then, use the 250 mL beaker to prepare a hot water bath and regulate it to 200 C. Moreover, prepare the scenario to analyze the solution for the presence of Pb2+, Hg22+, and Ag+ ions. Start by labelling the test tubes from 1-8. Then, use the tube 1 and add 10 drops of 10 cation solutions (note: the unknown solution must be in the tube 8). Next, add 8 drops of 6 M HCl and mix it, using a stirring rod.
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