Chemistry: Principles and Reactions
Chemistry: Principles and Reactions
8th Edition
ISBN: 9781305079373
Author: William L. Masterton, Cecile N. Hurley
Publisher: Cengage Learning
bartleby

Concept explainers

bartleby

Videos

Textbook Question
Chapter 13, Problem 51QAP

Barbituric acid, HC4H3N2O3, is used to prepare barbiturates, a class of drugs used as sedatives. Its Ka is 9.8 × 10 5 . Calculate [H+] in solutions prepared by adding enough water to the following to make 1.45 L.

(a) 0.344 mol

(b) 28.9 g

Expert Solution
Check Mark
Interpretation Introduction

(a)

Interpretation:

The concentration of hydrogen ion in the given solution should be calculated.

Concept introduction:

The dissociation reaction of a weak acid is represented as follows:

HBH++B

The expression for the acid dissociation constant will be as follows:

Ka=[H+][B][HB]

Here, [H+] is equilibrium concentration of hydrogen ion, [B] is equilibrium concentration of conjugate base and [HB] is the equilibrium concentration of weak acid.

Answer to Problem 51QAP

4.84×103 M

Explanation of Solution

The acid dissociation constant of barbituric acid is 9.8×105. The volume of solution is 1.45 L and number of moles of the acid is 0.344 mol.

The molarity of HC4H3N2O3 can be calculated as follows:

M=nV(L)

Putting the values,

M=0.344 mol1.45 L=0.24 M

Thus, the concentration of HC4H3N2O3 is 0.24 M.

The concentration all the species can be calculated using the ICE table as follows:

      HC4H3N2O3C4H3N2O3+H+I     0.24                    -               -C     -x                      x             xE     0.24-x                x             x

The expression for Ka is as follows:

Ka=[C4H3N2O3][H+][HC4H3N2O3]

Putting the values,

9.8×105=(x)(x)(0.24x)

On rearranging,

9.8×105(0.24)9.8×105x=x22.352×1059.8×105x=x2

Or,

x2+9.8×105x2.352×105=0

Comparing this with the general quadratic equation as follows:

ax2+bxc=0

Solving the quadratic equation,

x=b±b24ac2a

Putting the values,

x=9.8×105±(9.8×105)24(1)(2.352×105)2(1)=1.2×105±9.604×109+9.41×1052(1)=1.2×105±9.7×1032

x=4.84×103,4.856×103

Since, the value of x cannot be negative thus, the value of x will be 4.84×103.

From the ICE table, it is equal to the concentration of hydrogen ion thus,

[H+]=4.84×103

Therefore, the concentration of hydrogen ion is 4.84×103 M.

Expert Solution
Check Mark
Interpretation Introduction

(b)

Interpretation:

The concentration of hydrogen ion in the given solution should be calculated.

Concept introduction:

The dissociation reaction of a weak acid is represented as follows:

HBH++B

The expression for the acid dissociation constant will be as follows:

Ka=[H+][B][HB]

Here, [H+] is equilibrium concentration of hydrogen ion, [B] is equilibrium concentration of conjugate base and [HB] is the equilibrium concentration of weak acid.

Answer to Problem 51QAP

3.86×103 M

Explanation of Solution

The mass of barbituric acid is given as 28.9 g. The molecular formula of the barbituric acid is HC4H3N2O3 thus, its molar mass is 128.1 g/mol.

Now, from mass and molar mass of the HC4H3N2O3, its number of moles can be calculated as follows:

n=mM=28.9 g128.1 g/mol=0.2256 mol

Now, the molarity of HC4H3N2O3 can be calculated as follows:

M=nV(L)

Putting the values,

M=0.2256 mol1.45 L=0.156 M

Thus, the concentration of HC4H3N2O3 is 0.156 M.

The concentration all the species can be calculated using the ICE table as follows:

      HC4H3N2O3C4H3N2O3+H+I     0.156                    -               -C     -x                        x             xE     0.156-x                x            x

The expression for Ka is as follows:

Ka=[C4H3N2O3][H+][HC4H3N2O3]

Putting the values,

Ka=(x)(x)(0.156x)=9.8×105

On rearranging,

9.8×105(0.156)9.8×105x=x21.53×1059.8×105x=x2

Or,

x2+9.8×105x1.53×105=0

Comparing this with the general quadratic equation as follows:

ax2+bxc=0

Solving the quadratic equation,

x=b±b24ac2a

Putting the values,

x=9.8×105±(9.8×105)24(1)(1.53×105)2(1)=9.8×105±9.604×109+6.12×1052(1)=9.8×105±7.82×1032

x=3.86×103,3.96×103

Since, the value of x cannot be negative thus, the value of x will be 3.86×103.

From the ICE table, it is equal to the concentration of hydrogen ion thus,

[H+]=3.86×103

Therefore, the concentration of hydrogen ion is 3.86×103 M.

Want to see more full solutions like this?

Subscribe now to access step-by-step solutions to millions of textbook problems written by subject matter experts!
Students have asked these similar questions
Lactic acid, HC3H5O3, is a weak acid; write an equation for its ionization in aqueous solution. If 0.15 M solution of lactic acid has pH = 2.34, calculate the molar concentration of H3O+in the solution. What are the Ka of lactic acid and the degree of ionization of the acid?
15D.5.What is the difference between (a)monoprotic acid and a diprotic acid,(b) a weak acid and a strong acid, (c)an acid and a base? HCl, HBr, and HI are strong acids,yet HF is a weak acid. What does thismean in terms of the extent to whichthese substances are ionized insolution?Label each of the followingsubstances as an acid, base, salt, ornone of the above. Indicate whetherthe substance exists in aqueoussolution entirely in molecular form,entirely as ions, or as a mixture ofmolecules and ions. (a) HF; (b)acetonitrile, CH3CN; (c) NaClO4; (d)Ba(OH)2.
In a solution, [H+ ] = 3.25 x 10-10 M. What is its pH and is it considered an acid or a base?

Chapter 13 Solutions

Chemistry: Principles and Reactions

Ch. 13 - Using the Brønsted-Lowry model, write an equation...Ch. 13 - Prob. 12QAPCh. 13 - Find the pH of solutions with the following[ H+ ]....Ch. 13 - Find the pH of solutions with the following[ H+ ]....Ch. 13 - Calculate H+ and OH- and in solutions with the...Ch. 13 - Calculate [H+] and [OH-] in solutions with the...Ch. 13 - Complete the following table for solutions at 25C.Ch. 13 - Complete the following table for solutions at 25C.Ch. 13 - Solution 1 has [ H+ ]=1.7102 M. Solution 2 has [...Ch. 13 - Solution R has pH 13.42. Solution Q has [ OH...Ch. 13 - Consider three solutions, R, Z, and Q. •...Ch. 13 - Solution A has a pH of 12.32. Solution B has [H+]...Ch. 13 - Unpolluted rain water has a pH of about 5.5. Acid...Ch. 13 - Most cola soft drinks have a pH of 3.1. Green tea...Ch. 13 - Find [OH-] and the pH of the following solutions....Ch. 13 - Find [H+] and the pH of the following solutions....Ch. 13 - Find [OH+], [OH-] and the pH of the following...Ch. 13 - Find [OH-], [H+], and the pH of the following...Ch. 13 - How many grams of HI should be added to 265 mL of...Ch. 13 - What is the pH of a solution obtained by adding...Ch. 13 - What is the pH of a solution obtained by adding...Ch. 13 - What is the pH of a solution obtained by mixing...Ch. 13 - Write the ionization equation and the Ka for each...Ch. 13 - Write the ionization equation and the Ka...Ch. 13 - Calculate Ka for the weak acids that have the...Ch. 13 - Prob. 36QAPCh. 13 - Prob. 37QAPCh. 13 - Consider these acids (a) Arrange the acids in...Ch. 13 - Rank the following solutions in order of...Ch. 13 - Rank the following acids (M=0.10)in order of...Ch. 13 - Prob. 41QAPCh. 13 - Rank the solutions in Questions 40 in order of...Ch. 13 - The pH of a 0.129 M solution of a weak acid, HB,...Ch. 13 - The pH of a 2.642 M solution of a weak acid, HB,...Ch. 13 - Paraminobenzene (PABA), HC7H6NO2, is used in some...Ch. 13 - Acetaminophen, HC8H8NO2 (MM=151.17g/mol), is the...Ch. 13 - Caproic acid, HC6H11O2, is found in coconut oil...Ch. 13 - Barbituric acid, HC4H3N2O3, is used to prepare...Ch. 13 - When aluminum chloride dissolves in water,...Ch. 13 - Using the Ka values in Table 13.2, calculate the...Ch. 13 - Barbituric acid, HC4H3N2O3, is used to prepare...Ch. 13 - Penicillin(MM=356g/mol), an antibiotic often used...Ch. 13 - Gallic acid, HC7H5O5, an ingredient in some...Ch. 13 - Anisic acid (K a=3.38105) is found in anise seeds...Ch. 13 - Phenol, once known as carbolic acid, HC6H5O, is a...Ch. 13 - Benzoic acid (K a=6.6105)is present in many...Ch. 13 - Chromic acid, H2CrO4, is commonly obtained by...Ch. 13 - Consider citric acid, H3C6H5O7, added to many soft...Ch. 13 - Consider a 0.45 M solution of ascorbic...Ch. 13 - Consider a 0.33 M solution of the diprotic acid...Ch. 13 - Phthalic acid H2C8H4O4, is a diprotic acid. It is...Ch. 13 - Selenious acid, H2SeO3, is primarily used to...Ch. 13 - Write the ionization expression and the Kb...Ch. 13 - Follow the instructions for Question 63 for the...Ch. 13 - Prob. 65QAPCh. 13 - Follow the directions of Question 65 for the...Ch. 13 - Using the equilibrium constants listed in Table...Ch. 13 - Using the equilibrium constants listed in Table...Ch. 13 - Find the value of Kb for the conjugate base of the...Ch. 13 - Find the values of Kb for the conjugate bases of...Ch. 13 - Determine [OH-], pOH and pH of a 0.28 M aqueous...Ch. 13 - Determine the [OH-] and pH of a 0.72 M solution of...Ch. 13 - Codeine (Cod), a powerful and addictive...Ch. 13 - Consider pyridine, C5H5N, a pesticide and deer...Ch. 13 - A solution of baking soda, NaHCO3, has a pH of...Ch. 13 - A solution of sodium cyanide, NaCN, has a pH of...Ch. 13 - Write formulas for two salts that (a) contain Ni3+...Ch. 13 - Write formulas for two salts that (a) contain NH4+...Ch. 13 - State whether 1 M solutions of the following salts...Ch. 13 - State whether 1 M solutions of the following salts...Ch. 13 - Write net ionic equations to explain the acidity...Ch. 13 - Prob. 82QAPCh. 13 - Arrange the following aqueous 0.1 M solutions in...Ch. 13 - Arrange the following aqueous 0.1 M solutions in...Ch. 13 - Unclassified At 25C, a 0.20 M solution of...Ch. 13 - Prob. 86QAPCh. 13 - There are 324 mg of acetylsalicylic acid...Ch. 13 - A student is asked to bubble enough ammonia gas...Ch. 13 - Prob. 89QAPCh. 13 - A student prepares 455 mL of a KOH solution, but...Ch. 13 - Consider the process H2O H+(aq)+OH(aq)H=55.8kJ (a)...Ch. 13 - Household bleach is prepared by dissolving...Ch. 13 - A tablet with a mass of 4.08 g contains 71.2%...Ch. 13 - Consider a weak organic base (nonelectrolyte) with...Ch. 13 - Prob. 95QAPCh. 13 - Which of the following is/are true regarding a 0.1...Ch. 13 - Which of the following is/are true about a 0.10 M...Ch. 13 - Consider the following six beakers. All have 100...Ch. 13 - Each box represents an acid solution at...Ch. 13 - Each box represents an acid solution at...Ch. 13 - Prob. 101QAPCh. 13 - You are asked to determine whether an unknown...Ch. 13 - What is the pH of a 0.020 M solution of H2SO4? You...Ch. 13 - Prob. 104QAPCh. 13 - What is the pH of a solution obtained by mixing...Ch. 13 - A solution is made up of 273 mL of 0.164 M HNO3...Ch. 13 - What is the freezing point of vinegar, which is an...Ch. 13 - Prob. 108QAPCh. 13 - Consider two weak acids, HA (MM=138g/mol)and HB...Ch. 13 - Consider an aqueous solution of a weak base, NaB...
Knowledge Booster
Chemistry
Learn more about
Need a deep-dive on the concept behind this application? Look no further. Learn more about this topic, chemistry and related others by exploring similar questions and additional content below.
Similar questions
    • SEE MORE QUESTIONS
    Recommended textbooks for you
  • Chemistry: Principles and Reactions
    Chemistry
    ISBN:9781305079373
    Author:William L. Masterton, Cecile N. Hurley
    Publisher:Cengage Learning
    Chemistry: An Atoms First Approach
    Chemistry
    ISBN:9781305079243
    Author:Steven S. Zumdahl, Susan A. Zumdahl
    Publisher:Cengage Learning
    Chemistry
    Chemistry
    ISBN:9781133611097
    Author:Steven S. Zumdahl
    Publisher:Cengage Learning
  • Chemistry
    Chemistry
    ISBN:9781305957404
    Author:Steven S. Zumdahl, Susan A. Zumdahl, Donald J. DeCoste
    Publisher:Cengage Learning
    Chemistry by OpenStax (2015-05-04)
    Chemistry
    ISBN:9781938168390
    Author:Klaus Theopold, Richard H Langley, Paul Flowers, William R. Robinson, Mark Blaser
    Publisher:OpenStax
    Introduction to General, Organic and Biochemistry
    Chemistry
    ISBN:9781285869759
    Author:Frederick A. Bettelheim, William H. Brown, Mary K. Campbell, Shawn O. Farrell, Omar Torres
    Publisher:Cengage Learning
  • Chemistry: Principles and Reactions
    Chemistry
    ISBN:9781305079373
    Author:William L. Masterton, Cecile N. Hurley
    Publisher:Cengage Learning
    Chemistry: An Atoms First Approach
    Chemistry
    ISBN:9781305079243
    Author:Steven S. Zumdahl, Susan A. Zumdahl
    Publisher:Cengage Learning
    Chemistry
    Chemistry
    ISBN:9781133611097
    Author:Steven S. Zumdahl
    Publisher:Cengage Learning
    Chemistry
    Chemistry
    ISBN:9781305957404
    Author:Steven S. Zumdahl, Susan A. Zumdahl, Donald J. DeCoste
    Publisher:Cengage Learning
    Chemistry by OpenStax (2015-05-04)
    Chemistry
    ISBN:9781938168390
    Author:Klaus Theopold, Richard H Langley, Paul Flowers, William R. Robinson, Mark Blaser
    Publisher:OpenStax
    Introduction to General, Organic and Biochemistry
    Chemistry
    ISBN:9781285869759
    Author:Frederick A. Bettelheim, William H. Brown, Mary K. Campbell, Shawn O. Farrell, Omar Torres
    Publisher:Cengage Learning
    General Chemistry | Acids & Bases; Author: Ninja Nerd;https://www.youtube.com/watch?v=AOr_5tbgfQ0;License: Standard YouTube License, CC-BY