Concept explainers
(a)
Interpretation:
The more acidic group −NH3+ or −COOH in the neutral amino acid alanine needs to be determined.
Concept introduction:
Proteins are
(b)
Interpretation:
The percentage of each form-protonates (H2A+ ), neutral (HA) and deprotonated (A- ) in the aqueous solution at pH = 4.00 needs to be determined.
Concept introduction:
Proteins are biomolecules that are composed of certain monomer units such as amino acids. These are carboxylic acids with one amino group bonded on alpha-C atom of the molecule. These amino acids involve in condensation process to form peptides and polypeptides which further form complex protein molecules. Amino acids are the organic molecules with both
(c)
Interpretation:
The percentage of each form-protonates (H2A+ ), neutral (HA) and deprotonated (A- ) in the aqueous solution at pH = 8.50 needs to be determined.
Concept introduction:
Proteins are biomolecules that are composed of certain monomer units such as amino acids. These are carboxylic acids with one amino group bonded on alpha-C atom of the molecule. These amino acids involve in condensation process to form peptides and polypeptides which further form complex protein molecules. Amino acids are the organic molecules with both
(d)
Interpretation:
The pH at which the neutral form of alanine present in the maximum amount needs to be determined.
Concept introduction:
Proteins are biomolecules that are composed of certain monomer units such as amino acid. These are carboxylic acids with one amino group bonded on the alpha-C atom of the molecule. These amino acids involve in condensation process to form peptides and polypeptides which further form complex protein molecules. Amino acids are the organic molecules with both
Want to see the full answer?
Check out a sample textbook solutionChapter 23 Solutions
CHEMISTRY-MASTERINGCHEMISTRY W/ETEXT
- 16-27 Guanidine, p/Ca 13.6, is a very strong base, almost as basic as hydroxide ion. NH NH2+ II II H2N—C—NH2 + H2O H2N—C—NH2 + OH" Guanidine Guanidinium ion pKb = 13.6 Complete the Lewis structure for guanidine, showing all valence electrons. The remarkable basicity of guanidine is attributed to the fact that the positive charge on the guanidinium ion is delocalized by resonance over the three nitrogen atoms. This delocalization increases the stability of the guanidinium ion relative to the ammonium ion or substituted ammonium ions. Draw three equivalent contributing structures for the guanidinium ion and show by the use of curved arrows how these three contributors are related. Propose an explanation for the fact that protonation occurs on the C=NH nitrogen rather than on one of the —NH., nitrogens. (Hint: Consider the resonance stabilization of the structure formed by protonation on a —NH., nitrogen compared with the resonance stabilization of the structure formed by protonation on the =NH nitrogen.) Predict the N—C—N bond angles in the hybrid. Which is the stronger acid, the ammonium ion or the guanidinium ion?arrow_forwardFind the value of Kb for the conjugate base of the following organic acids. (a) picric acid used in the manufacture of explosives; Ka = 0.16 (b) trichloroacetic acid used in the treatment of warts; Ka = 0.20arrow_forwardAcid-Base Equilibria Many factors contribute to the acidity of organic compounds. Electronegativity, resonance, induction, hybridization, aromaticity, and atomic size, all play a role. In the following comparisons, you are asked to identify the factor(s) that would be most important to analyze when predicting relative acidity, and then to predict the trend in acidity and pKa values. For each of the following pairs of compounds answer the following two multiple-choice questions. 1. What factor(s) are the most important to consider when predicting the relative acidity of the two compounds? a. Electronegativity of the atom possessing the hydrogen. b. Resonance stabilization of the anionic conjugate base. c. Inductive stabilization of the anionic conjugate base. d. Hybridization of the atom possessing the hydrogen. e. The atomic size of the atom possessing the hydrogen.arrow_forward
- Given an amino acid, be able to draw the structure when it is placed in water at pH = 2, pH = 7, or pH = 13. Is the amine group protonated or not? Is the carboxylic group protonated or not?arrow_forwardCalculate the pH at 25°C of a 0.64M solution of anilinium chloride C6H5NH3Cl. Note that aniline C6H5NH2 is a weak base with a pKb of 4.87.arrow_forwardThe disinfectant phenol, C₆H₅OH, has a pKₐ of 10.0 in wa-ter, but 14.4 in methanol. (a) Why are the values different? (b) Is methanol is a stronger or weaker base than water? (c) Write the dissociation reaction of phenol in methanol. (d) Write an expres-sion for the autoionization constant of methanol.arrow_forward
- Give handwritten answerarrow_forwardWhat is the conjugate acid of H2C6H7O5 -1aq2? What is its conjugate base?arrow_forwardThe acid dissociation constant K of trimethylacetic acid (HC(CH³)CO₂) is 9.33 × 10¯. Calculate the pH of a 1.2M solution of trimethylacetic acid. Round your answer to 1 decimal place. pH = 0arrow_forward
- Calculate the pH of a 0.12 M solution of hydrocyanic acid (HCN), which has a pKa of 9.31. Your answer should have 3 significant figures (i.e. 9.99).arrow_forwardThe acid dissociation constant K, of trimethylacetic acid (HC (CH3) CO2 is 9.33 × 10 *. Calculate the pH of a 6.1M solution of trimethylacetic acid. Round your answer to 1 decimal place. PHarrow_forwardCalculate the pH of a 0.2 M solution of an amine that has a pKa of 9.5arrow_forward
- Chemistry: The Molecular ScienceChemistryISBN:9781285199047Author:John W. Moore, Conrad L. StanitskiPublisher:Cengage LearningChemistry: Principles and PracticeChemistryISBN:9780534420123Author:Daniel L. Reger, Scott R. Goode, David W. Ball, Edward MercerPublisher:Cengage LearningChemistry & Chemical ReactivityChemistryISBN:9781133949640Author:John C. Kotz, Paul M. Treichel, John Townsend, David TreichelPublisher:Cengage Learning
- Chemistry & Chemical ReactivityChemistryISBN:9781337399074Author:John C. Kotz, Paul M. Treichel, John Townsend, David TreichelPublisher:Cengage LearningOrganic ChemistryChemistryISBN:9781305580350Author:William H. Brown, Brent L. Iverson, Eric Anslyn, Christopher S. FootePublisher:Cengage LearningIntroduction to General, Organic and BiochemistryChemistryISBN:9781285869759Author:Frederick A. Bettelheim, William H. Brown, Mary K. Campbell, Shawn O. Farrell, Omar TorresPublisher:Cengage Learning