In glycine, the carboxylic acid group has \(K_{\mathrm{a}}=4.3 \times 10^{-3}\) and the amino group has \(K_{b}=6.0 \times 10^{-5} .\) Use these equilibrium constant values to calculate the cquilibrium constants for the following. a. \(^{+} \mathrm{H}_{3} \mathrm{NCH}_{2} \mathrm{CO}_{2}^{-}+\mathrm{H}_{2} \mathrm{O} \rightleftharpoons \mathrm{H}_{2} \mathrm{NCH}_{2} \mathrm{CO}_{2}^{-}+\mathrm{H}_{3} \mathrm{O}^{+}\) b. \(\mathrm{H}_{2} \mathrm{NCH}_{2} \mathrm{CO}_{2}^{-}+\mathrm{H}_{2} \mathrm{O} \rightleftharpoons \mathrm{H}_{2} \mathrm{NCH}_{2} \mathrm{CO}_{2} \mathrm{H}+\mathrm{OH}^{-}\) c. \(\mathbf{H}_{3} \mathrm{NCH}_{2} \mathrm{CO}_{2} \mathrm{H} \rightleftharpoons 2 \mathrm{H}^{+}+\mathrm{H}_{2} \mathrm{NCH}_{2} \mathrm{CO}_{2}^{-}\)

Short Answer

Expert verified
For the given reactions involving glycine, the equilibrium constants are: a. \(K_{a1}=4.3 \times 10^{-3}\) b. \(K_{b1}=6.0 \times 10^{-5}\) c. \(K_{c}=1.3953 \times 10^{-2}\)

Step by step solution

01

a. Calculate the equilibrium constant for the first reaction

First, let's define the equilibrium constants we already know: - Ka is the acid dissociation constant for the carboxylic acid group of glycine - Kb is the base dissociation constant for the amino group of glycine For the first reaction, we can treat it as a simple acid dissociation reaction: \(^{+} \mathrm{H}_{3} \mathrm{NCH}_{2} \mathrm{CO}_{2}^{-}+\mathrm{H}_{2} \mathrm{O} \rightleftharpoons \mathrm{H}_{2} \mathrm{NCH}_{2} \mathrm{CO}_{2}^{-}+\mathrm{H}_{3} \mathrm{O}^{+}\) In this reaction, the amino group of glycine is losing a proton. Therefore, Ka for this reaction would be equal to the given Ka value. So, \(K_{a1} = K_{a} = 4.3 \times 10^{-3}\).
02

b. Calculate the equilibrium constant for the second reaction

For the second reaction, it can be treated as a simple base dissociation reaction: \(\mathrm{H}_{2} \mathrm{NCH}_{2} \mathrm{CO}_{2}^{-}+\mathrm{H}_{2} \mathrm{O} \rightleftharpoons \mathrm{H}_{2} \mathrm{NCH}_{2} \mathrm{CO}_{2} \mathrm{H}+\mathrm{OH}^{-}\) In this reaction, the carboxylic acid group of glycine is gaining a proton. Therefore, Kb for this reaction would be equal to the given Kb value. So, \(K_{b1} = K_{b} = 6.0 \times 10^{-5}\).
03

c. Calculate the equilibrium constant for the third reaction

The third reaction is as follows: \(\mathrm{H}_{3} \mathrm{NCH}_{2} \mathrm{CO}_{2} \mathrm{H} \rightleftharpoons 2 \mathrm{H}^{+}+\mathrm{H}_{2} \mathrm{NCH}_{2} \mathrm{CO}_{2}^{-}\) This reaction can be considered as a combination of two reactions: the first given reaction in the reverse direction, and the second given reaction in the forward direction. This means that the equilibrium constant for this reaction can be calculated by multiplying the inverse of the equilibrium constant for the first reaction (Ka) with the equilibrium constant for the second reaction (Kb). Hence, for the third reaction, the equilibrium constant can be calculated as follows: \(K_{c} = \frac{1}{K_{a1}} \times K_{b1} = \frac{1}{4.3 \times 10^{-3}} \times 6.0 \times 10^{-5}\) Calculation: \(K_{c} = 1.3953 \times 10^{-2}\)

Unlock Step-by-Step Solutions & Ace Your Exams!

  • Full Textbook Solutions

    Get detailed explanations and key concepts

  • Unlimited Al creation

    Al flashcards, explanations, exams and more...

  • Ads-free access

    To over 500 millions flashcards

  • Money-back guarantee

    We refund you if you fail your exam.

Over 30 million students worldwide already upgrade their learning with Vaia!

One App. One Place for Learning.

All the tools & learning materials you need for study success - in one app.

Get started for free

Most popular questions from this chapter

Using appropriate reactants, alcohols can be oxidized into aldehydes, ketones, and/or carboxylic acids. Primary alcohols can be oxidized into aldehydes, which can then be oxidized into carboxylic acids. Secondary alcohols can be oxidized into ketones, while tertiary alcohols do not undergo this type of oxidation. Give the structure of the product(s) resulting from the oxidation of each of the following alcohols. a. 3 -methyl-l-butanol b. 3 -methyl- 2 -butanol c. 2 -methyl-2-butanol

Draw the isomer(s) specified. There may be more than one possible isomer for each part. a. a cyclic compound that is an isomer of trans-2-butene b. an ester that is an isomer of propanoic acid c. a ketone that is an isomer of butanal d. a secondary amine that is an isomer of butylamine e. a tertiary amine that is an isomer of butylamine f. an ether that is an isomer of 2 -methyl-2-propanol g. a secondary alcohol that is an isomer of 2-methyl-2-propanol

Draw the structural formula for each of the following. a. formaldehyde (methanal) b. 4 -heptanone c. 3 -chlorobutanal d. \(5,5-\) dimethyl- 2 -hexanone

If one hydrogen in a hydrocarbon is replaced by a halogen atom, the number of isomers that exist for the substituted compound depends on the number of types of hydrogen in the original hydrocarbon. Thus there is only one form of chloroethane (all hydrogens in ethane are equivalent), but there are two isomers of propane that arise from the substitution of a methyl hydrogen or a methylene hydrogen. How many isomers can be obtained when one hydrogen in each of the compounds named below is replaced by a chlorine atom? a. \(n\) -pentane c. 2,4 -dimethylpentane b. 2 -methylbutane d. methylcyclobutane

Reagents such as HCI, HBr, and HOH (H_O) can add across carbon-carbon double and triple bonds, with H forming a bond to one of the carbon atoms in the multiple bond and \(\mathrm{Cl}, \mathrm{Br},\) or OH forming a bond to the other carbon atom in the multiple bond. In some cases, two products are possible. For the major organic product, the addition occurs so that the hydrogen atom in the reagent attaches to the carbon atom in the multiple bond that already has the greater number of hydrogen atoms bonded to it. With this rule in mind, draw the structure of the major product in each of the following reactions. a. \(\mathrm{CH}_{3} \mathrm{CH}_{2} \mathrm{CH}=\mathrm{CH}_{2}+\mathrm{H}_{2} \mathrm{O} \stackrel{\mathrm{H}^{2}}{\longrightarrow}\) b. \(\mathrm{CH}_{3} \mathrm{CH}_{2} \mathrm{CH}=\mathrm{CH}_{2}+\mathrm{HBr} \longrightarrow\) c. \(\mathrm{CH}_{3} \mathrm{CH}_{2} \mathrm{C} \equiv \mathrm{CH}+2 \mathrm{HBr} \longrightarrow\)

See all solutions

Recommended explanations on Chemistry Textbooks

View all explanations

What do you think about this solution?

We value your feedback to improve our textbook solutions.

Study anywhere. Anytime. Across all devices.

Sign-up for free