3. Copy the five sets of data (volume NaOH and pH) from titration #3 into the table on the next page. Calculate the pKa for the unknown weak acid using one set of the data. Show the equations used to calculate concentrations of [A] eq and [HA] eq and show how these values are substituted into the rearranged Henderson-Hasselbalch equation (Eqn. 16.10).

3. Copy the five sets of data (volume NaOH and pH) from titration #3 into the table on the next page. Calculate the pKa for the unknown weak acid using one set of the data. Show the equations used to calculate concentrations of [A] eq and [HA] eq and show how these values are substituted into the rearranged Henderson-Hasselbalch equation (Eqn. 16.10).

Principles of Modern Chemistry

8th Edition

ISBN:9781305079113

Author:David W. Oxtoby, H. Pat Gillis, Laurie J. Butler

Publisher:David W. Oxtoby, H. Pat Gillis, Laurie J. Butler

Chapter15: Acid–base Equilibria

Section: Chapter Questions

Problem 99AP

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Figure 15-3 outlines the classic scheme for separating a mixture of insoluble chloride salts from one another. Explain the chemistry involved in the various steps of the figure.
A. What two compounds would be best to use in preparing a pH 9.0 buffer solution? justify your answer. Assume you have the acids and the sodium salts of their conjugate bases available to you. Answer: The two compounds best fo preparing a buffer solution with a pH of 9.0 would be hydrocyanic (HCN) and phenol (HOc6H5) because their pKa values are 9.40 and 9.80 respectively making their pH levels the closest to 9. B. WHat mass ration of sodium to acid is needed to prepare this buffer? C. Can this buffer solution better resist pH changes from a string acid addition or strong base addition?
4. In the titration of15.00 mL of 0.200 M HC with 0.100 M NaOH, calculate the pH after the addition of the following volumes of titrant (mL) ; (a) 0.00; (b) 10.00; (c)14.50 ; (d) 15.00; (e) 15.50: (f) 20.00 mL.
MeH When two Lewis bases are compared in the reaction with the given Lewis acid, what difference can you expect in any aspect of the reaction? Explain the difference with the proper theoretical principle. OLi Et VS Me H. Br OLi CS Scanned with CamScanner
In the experiment, we used titration to determine the total acid content ofsamples, which we reported in terms of molarity. Reporting acidity through pHmeasurements is quite different, in that we can only measure the amount of theacid in its ionized form. You were tasked to investigate a clear aqueous solutionof an unknown monoprotic acid. You decided to use two methods togather data.Method 1 – TITRATION: A 10. mL aliquot of the sample was diluted with 25 mLdistilled water. Two drops of phenolphthalein were added and then it was titrated3.54 mL of 0.048 M standardized NaOH to the endpoint.Method 2 – pH STRIP: You took 1 mL of the sample and used a pH strip toestimate the pH, which turned out to be around 3.3. Another 1 mL of the samplewas diluted with 9 mL of water. The pH was taken again and is now around 3.8.a) Calculate the molarity of the acid using the titration data.b) If we assume that the titrated unknown is a strong acid, predict thepH of the sample.c) Using pH strip results,…
2. In the pH metric titration of strong and weak acid mixture against strong alkali, generally first peak is weaker while the second peak is stronger-why?
3. Copy the five sets of data (volume NaOH and pH) from titration #3 into the table on the next page. Calculate the pKa for the unknown weak acid using one set of the data. Show the equations used to calculate concentrations of [A] eq and [HA] eq and show how these values are substituted into the rearranged Henderson-Hasselbalch equation (Eqn. 16.10).
3) Arsenic acid has 3 pK's: 2.19, 6.94, and 11.51. Detemine the concentrations of all the species (H,ASO, → ASO, ) at pH 7.00. Would this be a good buffer at this pH? Explain. 4) For a 0.500 M solution of HOAC at pH 4.757, how much KOH (in g) needs to be added to get to pH 5.136? 5) A certain monoprotic weak acid gave a pH of 2.336 when a 0.447 M solution was made. What is the pK,?
A professor prepares a buffer solution that they need for the purification of protein from human cell lysates. They did mix weak acid and conjugate base and obtained an INITIAL solution, which is characterized by the parameters shown in the images. Unfortunately, they did not pay attention to the instructions and added an additional 5 ml of 1M HCl to the initial solution. They were then wondering whether they can still use the solution for their purification experiment and what the pH of the resulting FINAL buffer solution would be? Determine the LINAL H and provide it in the answer how to one decimal place. Chang pH addition of strong base or acid_004 ed answer. Note: You may Hydrochloric Acid M Solution IS17013 500 ml 1 M HCI Final volume of solution: 200 ml Total buffer compound concentration: 150 mM ASSCO Initial concentration weak acid: 0.036 M Initial concentration conjugate base: 0.114 M INITIAL pH of solution: 3.1 Buffer compound pk₂: 2.6 14 13 12 11 10 9
Methodolody: (Include a short summary of the overall experimental plan you are going to run. You may use flow chart or bullet form for this part. Sketches of any experimental set-ups used in the experiment or the workup procedures). Preparation of buffers Prepare 250ml of the following buffer solutions. Concentration Buffer solution pka Desired ph 0.50 M Phosphate 2.12 3.0
Phenol red is a common acid-base indicator. It has a pKa equal to 8.000. Its undissociated form is yellow and its anionic form is violet. What is the concentration ratio between the acidic form vs. the basic form, [H- PRED]/[PRed], of the pH = 7.50 solution? Hint: Determine the concentration ratio of methyl red and its conjugate.
3) Arsenic acid has 3 pK,'s: 2.19, 6.94, and 11.51. Determine the concentrations of all the species (HASO. > ASO.) at pH 7.00. Would this be a good buffer at this pH? Explain. 4) For a 0.500M solution of HOAC at pH 4.757, how much KOH (in g) needs to be added to get to pH 5.136?