6. On the following titration curve of an unknown amino acid, label (and estimate) the pKa's of the amino acid. Consult the table of amino acid pKa's and predict the identity of the mystery amino acid. Estimate the pl of this amino acid. Draw the primary ionization state observed for this amino acid at each of the following pH's: 1, 4, 8, and 12. M AD 10 40 16 204 104 mes Off-added

6. On the following titration curve of an unknown amino acid, label (and estimate) the pKa's of the amino acid. Consult the table of amino acid pKa's and predict the identity of the mystery amino acid. Estimate the pl of this amino acid. Draw the primary ionization state observed for this amino acid at each of the following pH's: 1, 4, 8, and 12. M AD 10 40 16 204 104 mes Off-added

Appl Of Ms Excel In Analytical Chemistry

2nd Edition

ISBN:9781285686691

Author:Crouch

Publisher:Crouch

Chapter8: Polyfunctional Acids And Bases

Section: Chapter Questions

Problem 14P

See similar textbooks

Similar questions

•The pKa for acetic acid is 4.756 and the pKa for NH4+ is 9.245. What pH do you expect for the solutions with [A-]init [HA]init? Explain this by referring to the acid = dissociation constant expressions (Ka) for NH4+ and CH3COOH as well as your answer to part (a). Do your measurements agree with your expectations (make specific reference to your experimental data and consider uncertainty)?
Title: Potentiometric Acid Titration fitulo:Tabla de ph volumen NaOH (ml) ph Titulación NaOH 20 4.25 7.39 20.1 6.24 7.03 7.21 6.83 6.59 20.2 6.59 6.24 20.3 6.83 6 20.4 7.03 4.25 20.5 7.21 20.6 7.39 1 19.9 20 20.1 20.2 20.3 20.4 20.5 20.6 20.7 V NAOH (ml) With the previous graph determine the following: a. Determine the bufer zone on the graph b. Determine the volume at the stoichiometric point of the acid titration c. Determine the average volume d. Use the medium volume to get the pka e. From pka, get the value of ka
Leucine has two dissociable protons: one with a pKa of 2.3, the other with a pKa of 9.7. Sketch a properly labeled titration curve for leucine titrated with NaOH; indicate where the pH = pI and the region(s) in which buffering occurs. Please be as precise as possible in the way you draw your graph (axis, units, position of data points, etc....).
Calculate the pH at each of the following points for the titration of 100 mL of 0. 6 M dl-Histidine with the following volumes of 1.20 M sodium hydroxide. H3His + H* + H,His Ka1 = 3.98x10-3 H2His + H* + HHis2- Ka2 = 9.12x1o:7 HHİS2. + H* + His3. Ka3 = 4.67x1o 10 Vol. of NaOH Calculated pH O mL 30 mL 50 mL
The following is list of weak acids and their pką values weak acid pKa benzoic acid 4.20 hydrogen citrate 6.40 hydrocyanic acid 9.31 hydrogen phosphate 12.38 Which would be the best buffer to use at pH 7 ? For benzoic acid, a 50:50 mixture of benzoic acid and its conjugate base, the benzoate ion, would have pH = The buffering capacity of a benzoic acid:benzoate buffer would be at pH = 7 A. 4.20 B. 6.40 C. 9.31 D. 12.38 E. benzoic acid F. hydrogen citrate G. hydrocyanic acid H. hydrogen phosphate I. good J. bad
Calculate the pH at each of the following points for the titration of 100 mL of 0. 6 M dl-Histidine with the following volumes of 1.20 M sodium hydroxide. H3His + H* + H2His Ka1 = 3.98x10-3 H2His + H* + HHis2- Ka2 = 9.12x1o7 HHİS2- + H* + His3- Ka3 = 4.67x10-10 Vol. of NaOH Calculated pH O mL 30 mL 50 mL 75 mL 100 mL 125 mL 135 mL 150 mL 175 mL Please provide a sketch of the titration curve and label both the x & y axis and applicable equations used at each data point (e.g., pH = - log[H*] or pH = pk, or pH = pK, + log )
Sketch a titration curve of the amino acid isoleucine with pH on the y-axis and volume of titrant on the x-axis. Label each axis appropriately. Draw the chemical structures of the 3 possible forms of isoleucine in aqueous solution. Indicate on the graph the following: where each of the species predominates, the pKa values and the isoelectric point.
11. The titration curve for an amino acid is given below. According to this titration curve, the questions given below please reply. A)How many amino acids is this? Does it have an ionizable group? B)Each of the ionizable groups What are the pKa values? C)A good buffer of this amino acid pH ranges in which it will function as Please specify. Graph buffering zones by enclosing a rectangle on you can show. D)This titration curve is composed of amino acids whose structures are given below. which may belong. Circle your choice of the amino acid you have chosen. specify your name.
Based on the graph, the retention of 4-aminobenzoic acid is not affected changes in mobile phase pH because it is zwitterionic. True of Flase?
Calculate the pH of 50mls of 0.1100M arginine to which 20 mls PH of 0.1005M Hcl have been added.
7. A 10.0 cm³ sample of 0.150 mol dm³ aminoethanoic acid with a pH of 5.3 was titrated with 0.100 mol dm³ NaOH. After 20.0 cm³ of NaOH, an excess, had been added, the pH was found to be 12.5. Using the following axes, sketch a graph showing how the pH changes during this titration. 14 12 10 8. nH
20. Which of the following acid/ conjugate base pairs would function best as a buffer at physiological pH? a Lactic acid / Lactate ion; pKa = 3.86 b Carbonic acid / Bicarbonate ion; pKa = 6.37 c Bicarbonate ion / Carbonate ion; pKa = 10.25 d Dihydrogen phosphate / Monohydrogen phosphate ion; pKa = 6.86 e Acetic acid / Acetate ion; pKa = 4.76