C you have a solution containing 1 mol of each of

c) You have a solution containing 1 mol of each of these unknown amino acids in a mixture at pH 6.5.
What would be the pH if you added 0.3 mol of HCl?

9/11/21, 4:57 PM Chapter 3 problems with solutions: CHEM 3510-001 Fall 2021 Biological Chemistry I
Equil 0.54 0.46
pH = 6 + log (0.46/0.54) = 5.93
d) What are the pI values of the two amino acids?
11/18
7) Consider the pH profile shown below for titration of a single amino acid and the table of
pKas shown in Problem 6 above.
__H__ (a) What is the one letter code for the amino acid that is being titrated?
For all the following questions, use the letters above the titration to answer the question. Note that
there may be multiple answers to some of the questions.
__A__(b) This amino acid is present predominantly in a +2 net charge.

9/11/21, 4:57 PM Chapter 3 problems with solutions: CHEM 3510-001 Fall 2021 Biological Chemistry I
__B__(c) The average net charge of the amino acid is +1.5.
__ F__(d) Half of the amino groups are ionized.
__B__ (e) The pH is equal to the p K of the carboxyl group.
___F__ (f) The pH is equal to the p K of the amino group.
_BDF_ (g) The amino acid has its maximum buffering capacity.
_E_ (h) The average net charge of amino acid is zero.
12/18
__G__ (l) The average net charge of the amino acid is -1.
__D__ (m) Amino acid is present predominantly as a 50:50 mixture of the +1 and 0 charge states.