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Chemistry

Chemical Principles | 8th Edition | ISBN: 9781305581982 | Authors: Steven S. Zumdahl

Chemical Principles 8th Edition solutions

Author: Steven S. Zumdahl
Publisher: Brooks Cole
ISBN: 9781305581982
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Chapter 7 Problems

Chapter: 7 Problem: 7.1

Chemical Principles 8
Vinegar contains acetic acid and is used in salad dressings. What if acetic acid was a strong acid instead of a weak acid? Would it be safe to use vinegar as a salad dressing?

Chapter: 7 Problem: 7.2

Chemical Principles 8
What if you lived on a planet identical to earth but for which room temperature was 50C. How would the pH scale be different?

Chapter: 7 Problem: 7.3

Chemical Principles 8
Consider two aqueous solutions of different weak acids, HA and HB. What if all you know about the two acids is that the Ka value for HA is greater than that for HB? Can you tell which of the acids is stronger than the other? Can you tell which of the acid solutions has the lower pH? Defend your answe

Chapter: 7 Problem: 7.4

Chemical Principles 8
What if the three values of Ka for phosphoric acid were closer to each other in value? Why would this complicate the calculation of the pH for an aqueous solution of phosphoric acid?

Chapter: 7 Problem: 7.5

Chemical Principles 8
Consider two beakers of pure water at different temperatures. How do their pH values compare? Which is more acidic? More basic? Explain.

Chapter: 7 Problem: 7.6

Chemical Principles 8
Differentiate between the terms strength and concentration as they apply to acids and bases. When is HCl strong? Weak? Concentrated? Dilute? Answer the same questions for ammonia.

Chapter: 7 Problem: 7.7

Chemical Principles 8
Sketch two graphs: (a) percent dissociation of weak acid HA versus initial concentration of HA ([HA]0), and (b) H1 concentration versus [HA]0. Explain both.

Chapter: 7 Problem: 7.8

Chemical Principles 8
Consider a solution prepared by mixing a weak acid HA and HCl. What are the major species? Explain what is occurring in solution. How would you calculate the pH? What if you added NaA to this solution? Then added NaOH?

Chapter: 7 Problem: 7.9

Chemical Principles 8
Explain why salts can be acidic, basic, or neutral, and show examples. Do so without specific numbers.

Chapter: 7 Problem: 7.10

Chemical Principles 8
Consider two separate aqueous solutions: one of a weak acid HA and one of HCl. Assuming you started with 10 molecules of each: a. Draw a picture of what each looks like at equilibrium. b. What are the major species in each beaker? c. From your pictures, calculate the Ka values of each acid. d. Order

Chapter: 7 Problem: 7.11

Chemical Principles 8
You are asked for the H1 concentration in a solution of NaOH(aq). Because sodium hydroxide is a strong base, can we say there is no H1, since having H1 would imply that the solution is acidic?

Chapter: 7 Problem: 7.12

Chemical Principles 8
Consider a solution prepared by mixing equal moles of a weak acid HA, HCl, and NaA. Which of the following best describes what happens? a. The H1 from the HCl reacts completely with the A2 from the NaA. Then the HA dissociates to some extent. b. The H1 from the HCl reacts with the A2 from the NaA to

Chapter: 7 Problem: 7.13

Chemical Principles 8
Consider a solution formed by mixing 100.0 mL of 0.10 M HA (Ka 5 1.0 3 1026), 100.0 mL of 0.10 M NaA, and 100.0 mL of 0.05 M HCl. In calculating the pH for the final solution, you would make some assumptions about the order in which various reactions occur to simplify the calculations. State these as

Chapter: 7 Problem: 7.14

Chemical Principles 8
A certain sodium compound is dissolved in water to liberate Na1 ions and a particular negative ion. What evidence would you look for to determine whether the anion is behaving as an acid or a base (without measuring the pH of the solution)? Explain how the anion could behave simultaneously as an acid

Chapter: 7 Problem: 7.15

Chemical Principles 8
Acids and bases can be thought of as chemical opposites (acids are proton donors, and bases are proton acceptors). Therefore, one might think that Ka 5 1/Kb. Why isnt this the case? What is the relationship between Ka and Kb? Prove it with a derivation.

Chapter: 7 Problem: 7.16

Chemical Principles 8
You have two solutions of the salts NaX(aq) and NaY(aq) at equal concentrations. What would you need to know to determine which solution has the higher pH? Explain how you would decide (perhaps even provide a sample calculation).

Chapter: 7 Problem: 7.17

Chemical Principles 8
Is the conjugate base of a weak acid a strong base? Explain. Explain why Cl2 does not affect the pH of an aqueous solution.

Chapter: 7 Problem: 7.18

Chemical Principles 8
Match the following pH values: 1, 2, 5, 6, 6.5, 8, 11, 11, and 13 with the following chemicals (of equal concentration): HBr, NaOH, NaF, NaCN, NH4F, CH3NH3F, HF, HCN, and NH3. Answer this question without performing calculations.

Chapter: 7 Problem: 7.19

Chemical Principles 8
The salt BX, when dissolved in water, produces an acidic solution. Which of the following could be true? (There may be more than one correct answer.) a. The acid HX is a weak acid. b. The acid HX is a strong acid. c. The cation B1 is a weak acid. Explain

Chapter: 7 Problem: 7.20

Chemical Principles 8
Why is the pH of water at 258C equal to 7.00?

Chapter: 7 Problem: 7.21

Chemical Principles 8
Can the pH of a solution be negative? Explain. True or false: A strong acid solution always has a lower pH than a weak acid solution. Explain.

Chapter: 7 Problem: 7.22

Chemical Principles 8
Consider the autoionization of liquid ammonia: + + + Label each of the species in the equation as an acid or a base and explain your answer. 19. The following are representations of acidbase reactions: + + + + + + a. Label each of the species in both equations as an acid or a base and explain. b.

Chapter: 7 Problem: 7.23

Chemical Principles 8
Consider the following statements. Write out an example reaction and K expression that are associated with each statement. a. The autoionization of water. b. An acid reacts with water to produce the conjugate base of the acid and the hydronium ion. c. A base reacts with water to produce the conjugate

Chapter: 7 Problem: 7.24

Chemical Principles 8
For each of the following aqueous reactions, identify the acid, the base, the conjugate base, and the conjugate acid. a. Al1H2O2 6 31 1 H2OmH3O1 1 Al1H2O2 5 1OH2 21 b. H2O 1 HONH3 1mHONH2 1 H3O1 c. HOCl 1 C6H5NH2mOCl2 1 C6H5NH3 1

Chapter: 7 Problem: 7.25

Chemical Principles 8
Write balanced equations that describe the following reactions. a. The dissociation of perchloric acid in water. b. The dissociation of propanoic acid (CH3CH2CO2H) in water. c. The dissociation of ammonium ion in water.

Chapter: 7 Problem: 7.26

Chemical Principles 8
Write the dissociation reaction and the corresponding Ka equilibrium expression for each of the following acids in water. a. HCN b. HOC6H5 c. C6H5NH3

Chapter: 7 Problem: 7.27

Chemical Principles 8
Classify each of the following as a strong acid or a weak acid. c. d. Cl S O H

Chapter: 7 Problem: 7.28

Chemical Principles 8
Consider the following illustrations: H+ A B Which beaker best illustrates what happens when the following acids are dissolved in water? a. HNO2 d. HF b. HNO3 e. HC2H3O2

Chapter: 7 Problem: 7.29

Chemical Principles 8
Write the reaction and the corresponding Kb equilibrium expression for each of the following substances (acting as bases in water). a. NH3 c. pyridine, C5H5N b. CN2 d. aniline, C6H5NH2

Chapter: 7 Problem: 7.30

Chemical Principles 8
Use Table 7.2 to order the following from the strongest to the weakest acid. HClO2, H2O, NH4 1, HClO4

Chapter: 7 Problem: 7.31

Chemical Principles 8
Use Table 7.2 to order the following from the strongest to the weakest base. ClO2 2, H2O, NH3, ClO4 2

Chapter: 7 Problem: 7.32

Chemical Principles 8
You may need Table 7.2 to answer the following questions. a. Which is the stronger acid, HCl or H2O? b. Which is the stronger acid, H2O or HNO2? c. Which is the stronger acid, HCN or HOC6H5?

Chapter: 7 Problem: 7.33

Chemical Principles 8
You may need Table 7.2 to answer the following questions. a. Which is the stronger base, Cl2 or H2O? b. Which is the stronger base, H2O or NO2 2? c. Which is the stronger base, CN2 or OC6H5 2?

Chapter: 7 Problem: 7.34

Chemical Principles 8
Consider the reaction of acetic acid in water CH3CO2H(aq) 1 H2O(l) 34 CH3CO2 2(aq) 1 H3O1(aq) where Ka 5 1.8 3 1025. a. Which two bases are competing for the proton? b. Which is the stronger base? c. In light of your answer to part b, why do we classify the acetate ion (CH3CO2 2) as a weak base? Use

Chapter: 7 Problem: 7.35

Chemical Principles 8
In general, as base strength increases, conjugate acid strength decreases. Explain why the conjugate acid of the weak base NH3 is a weak acid.

Chapter: 7 Problem: 7.36

Chemical Principles 8
Classify each of the following as a strong acid, weak acid, strong base, or weak base in aqueous solution. a. HNO2 b. HNO3 c. CH3NH2 g. O B O OHHC d. NaOH h. Ca(OH)2 e. NH3 i. H2SO4 f. HF

Chapter: 7 Problem: 7.37

Chemical Principles 8
The pH of a sample of gastric juice in a persons stomach is 2.1. Calculate the pOH, [H1], and [OH2] for this sample. Is gastric juice acidic or basic?

Chapter: 7 Problem: 7.38

Chemical Principles 8
The pOH of a sample of baking soda dissolved in water is 5.74 at 258C. Calculate the pH, [H1], and [OH2] for this sample. Is the solution acidic or basic?

Chapter: 7 Problem: 7.39

Chemical Principles 8
Values of Kw as a function of temperature are as follows: Temp (8C) Kw 0 1.14 3 10215 25 1.00 3 10214 35 2.09 3 10214 40. 2.92 3 10214 50. 5.47 3 10214 a. Is the autoionization of water exothermic or endothermic? b. What is the pH of pure water at 50.8C? c. From a plot of ln(Kw) versus 1/T (using the

Chapter: 7 Problem: 7.40

Chemical Principles 8
At 40.8C the value of Kw is 2.92 3 10214. a. Calculate the [H1] and [OH2] in pure water at 40.8C. b. What is the pH of pure water at 40.8C? c. If the hydroxide ion concentration in a solution is 0.10 M, what is the pH at 40.8C?

Chapter: 7 Problem: 7.41

Chemical Principles 8
Give the conditions for a neutral aqueous solution at 258C, in terms of [H1], pH, and the relationship between [H1] and [OH2]. Do the same for an acidic solution and for a basic solution. As a solution becomes more acidic, what happens to pH, pOH, [H1], and [OH2]? As a solution becomes more basic, wh

Chapter: 7 Problem: 7.42

Chemical Principles 8
Calculate the [H1] of each of the following solutions at 258C. Identify each solution as neutral, acidic, or basic. a. [OH2] 5 1.5 M b. [OH2] 5 3.6 3 10215 M c. [OH2] 5 1.0 3 1027 M d. [OH2] 5 7.3 3 1024 M Also calculate the pH and pOH of each of these solutions.

Chapter: 7 Problem: 7.43

Chemical Principles 8
Calculate the [OH2] of each of the following solutions at 258C. Identify each solution as neutral, acidic, or basic. a. [H1] 5 1.0 3 1027 M b. [H1] 5 8.3 3 10216 M c. [H1] 5 12 M d. [H1] 5 5.4 3 1025 M Also calculate the pH and pOH of each of these solutions.

Chapter: 7 Problem: 7.44

Chemical Principles 8
Calculate [H1] and [OH2] for each solution at 258C. Identify each solution as neutral, acidic, or basic. a. pH 5 7.40 (the normal pH of blood) b. pH 5 15.3 c. pH 5 21.0 d. pH 5 3.20 e. pOH 5 5.0 f. pOH 5 9.60

Chapter: 7 Problem: 7.45

Chemical Principles 8
Fill in the missing information in the following table. pH pOH [H1] [OH2] Acidic, Basic, or Neutral? Solution a 9.63 Solution b 3.9 3 1026 M Solution c 0.027 M Solution d 12.2

Chapter: 7 Problem: 7.46

Chemical Principles 8
Calculate the pH of each of the following solutions of a strong acid in water. a. 0.10 M HCl c. 1.0 3 10211 M HI b. 5.0 M HClO4

Chapter: 7 Problem: 7.47

Chemical Principles 8
A solution is prepared by adding 50.0 mL of 0.050 M HBr to 150.0 mL of 0.10 M HI. Calculate [H1] and the pH of this solution. HBr and HI are both considered strong acids.

Chapter: 7 Problem: 7.48

Chemical Principles 8
How would you prepare 1600 mL of a pH 5 1.50 solution using concentrated (12 M) HCl?

Chapter: 7 Problem: 7.49

Chemical Principles 8
What mass of HNO3 is present in 250.0 mL of a nitric acid solution having a pH 5 5.10?

Chapter: 7 Problem: 7.50

Chemical Principles 8
What are the major species present in 0.250 M solutions of each of the following acids? Calculate the pH of each of these solutions. a. HNO2 b. CH3CO2H (HC2H3O2)

Chapter: 7 Problem: 7.51

Chemical Principles 8
What are the major species present in 0.250 M solutions of each of the following acids? Calculate the pH of each of these solutions. a. HOC6H5 b. HCN

Chapter: 7 Problem: 7.52

Chemical Principles 8
Calculate the concentration of all species present and the pH of a 0.020 M HF solution.

Chapter: 7 Problem: 7.53

Chemical Principles 8
Calculate the percent dissociation for a 0.22 M solution of chlorous acid (HClO2, Ka 5 1.2 3 1022)

Chapter: 7 Problem: 7.54

Chemical Principles 8
The following illustration displays the relative number of species when an acid, HA, is added to water. a. Is HA a weak or strong acid? How can you tell? b. Using the relative numbers given in the illustration, determine the value for Ka and the percent dissociation of the acid. Assume the initial ac

Chapter: 7 Problem: 7.55

Chemical Principles 8
Monochloroacetic acid (HC2H2ClO2) is a skin irritant that is used in chemical peels intended to remove the top layer of dead skin from the face and ultimately improve the complexion. The value of Ka for monochloroacetic acid is 1.35 3 1023. Calculate the pH of a 0.10 M solution of monochloroacetic ac

Chapter: 7 Problem: 7.56

Chemical Principles 8
Calculate the pH of a 0.010 M solution of iodic acid (HIO3, Ka 5 0.17).

Chapter: 7 Problem: 7.57

Chemical Principles 8
For propanoic acid (HC3H5O2, Ka 5 1.3 3 1025), determine the concentration of all species present, the pH, and the percent dissociation of a 0.100 M solution.

Chapter: 7 Problem: 7.58

Chemical Principles 8
A solution is prepared by dissolving 0.56 g of benzoic acid (C6H5CO2H, Ka 5 6.4 3 1025) in enough water to make 1.0 L of solution. Calculate [C6H5CO2H], [C6H5CO2 2], [H1], [OH2], and the pH of this solution.

Chapter: 7 Problem: 7.59

Chemical Principles 8
At 258C a saturated solution of benzoic acid (see Exercise 55) has a pH of 2.80. Calculate the water solubility of benzoic acid in moles per liter and grams per 100. mL.

Chapter: 7 Problem: 7.60

Chemical Principles 8
A typical aspirin tablet contains 325 mg of acetylsalicylic acid (HC9H7O4). Calculate the pH of a solution that is prepared by dissolving two aspirin tablets in one cup (237 mL) of solution. Assume the aspirin tablets are pure acetylsalicylic acid, Ka 5 3.3 3 1024

Chapter: 7 Problem: 7.61

Chemical Principles 8
Calculate the pH of a solution that contains 1.0 M HF and 1.0 M HOC6H5. Also calculate the concentration of OC6H5 2 in this solution at equilibrium.

Chapter: 7 Problem: 7.62

Chemical Principles 8
A solution contains a mixture of acids: 0.50 M HA (Ka 5 1.0 3 1023), 0.20 M HB (Ka 5 1.0 3 10210), and 0.10 M HC (Ka 5 1.0 3 10212). Calculate the [H1] in this solution

Chapter: 7 Problem: 7.63

Chemical Principles 8
A solution is made by adding 50.0 mL of 0.200 M acetic acid (Ka 5 1.8 3 1025) to 50.0 mL of 1.00 3 1023 M HCl. a. Calculate the pH of the solution. b. Calculate the acetate ion concentration.

Chapter: 7 Problem: 7.64

Chemical Principles 8
Calculate the pH of each of the following. a. a solution containing 0.10 M HCl and 0.10 M HOCl b. a solution containing 0.050 M HNO3 and 0.50 M HC2H3O2

Chapter: 7 Problem: 7.65

Chemical Principles 8
A 0.15 M solution of a weak acid is 3.0% dissociated. Calculate Ka.

Chapter: 7 Problem: 7.66

Chemical Principles 8
An acid HX is 25% dissociated in water. If the equilibrium concentration of HX is 0.30 M, calculate the Ka value for HX.

Chapter: 7 Problem: 7.67

Chemical Principles 8
Calculate the percent dissociation of the acid in each of the following solutions. a. 0.50 M acetic acid b. 0.050 M acetic acid c. 0.0050 M acetic acid d. Use Le Chteliers principle to explain why percent dissociation increases as the concentration of a weak acid decreases. e. Even though the percent

Chapter: 7 Problem: 7.68

Chemical Principles 8
The pH of a 1.00 3 1022 M solution of cyanic acid (HOCN) is 2.77 at 258C. Calculate Ka for HOCN from this result.

Chapter: 7 Problem: 7.69

Chemical Principles 8
Trichloroacetic acid (CCl3CO2H) is a corrosive acid that is used to precipitate proteins. The pH of a 0.050 M solution of trichloroacetic acid is the same as the pH of a 0.040 M HClO4 solution. Calculate Ka for trichloroacetic acid.

Chapter: 7 Problem: 7.70

Chemical Principles 8
A typical sample of vinegar has a pH of 3.0. Assuming that vinegar is only an aqueous solution of acetic acid (Ka 5 1.8 3 1025), calculate the concentration of acetic acid in vinegar.

Chapter: 7 Problem: 7.71

Chemical Principles 8
You have 100.0 g of saccharin, a sugar substitute, and you want to prepare a pH 5 5.75 solution. What volume of solution can be prepared? For saccharin (HC7H4NSO3), pKa 5 11.70 (pKa 5 2log Ka).

Chapter: 7 Problem: 7.72

Chemical Principles 8
Using Table 7.3, order the following bases from strongest to weakest. NO3 2, H2O, NH3, and C5H5N

Chapter: 7 Problem: 7.73

Chemical Principles 8
Using Table 7.3, order the following acids from strongest to weakest. HNO3, H2O, NH4 1, and C5H5NH1

Chapter: 7 Problem: 7.74

Chemical Principles 8
Use Table 7.3 to help answer the following questions. a. Which is the stronger base, ClO4 2 or C6H5NH2? b. Which is the stronger base, H2O or C6H5NH2? c. Which is the stronger base, OH2 or C6H5NH2? d. Which is the stronger base, C6H5NH2 or CH3NH2?

Chapter: 7 Problem: 7.75

Chemical Principles 8
Use Table 7.3 to help answer the following questions. a. Which is the stronger acid, HClO4 or C6H5NH3 1? b. Which is the stronger acid, H2O or C6H5NH3 1? c. Which is the stronger acid, C6H5NH3 1 or CH3NH3 1?

Chapter: 7 Problem: 7.76

Chemical Principles 8
Calculate the pH of the following solutions. a. 0.10 M NaOH c. 2.0 M NaOH b. 1.0 3 10210 M NaOH

Chapter: 7 Problem: 7.77

Chemical Principles 8
Calculate [OH2], pOH, and pH for each of the following. a. 0.00040 M Ca(OH)2 b. a solution containing 25 g of KOH per liter c. a solution containing 150.0 g of NaOH per liter

Chapter: 7 Problem: 7.78

Chemical Principles 8
Calculate the concentration of an aqueous Ba(OH)2 solution that has pH 5 10.50

Chapter: 7 Problem: 7.79

Chemical Principles 8
What mass of KOH is necessary to prepare 800.0 mL of a solution having a pH 5 11.56?

Chapter: 7 Problem: 7.80

Chemical Principles 8
For the reaction of hydrazine (N2H4) in water. H2NNH2(aq) 1 H2O(l) 34 H2NNH3 1(aq) 1 OH2(aq) Kb is 3.0 3 1026. Calculate the concentrations of all species and the pH of a 2.0 M solution of hydrazine in water.

Chapter: 7 Problem: 7.81

Chemical Principles 8
Calculate the percentage of pyridine (C5H5N) that forms pyridinium ion, C5H5NH1, in a 0.10 M aqueous solution of pyridine (Kb 5 1.7 3 1029).

Chapter: 7 Problem: 7.82

Chemical Principles 8
The presence of what element most commonly results in basic properties for an organic compound? What is present on this element in compounds that allows it to accept a proton?

Chapter: 7 Problem: 7.83

Chemical Principles 8
Calculate [OH2], [H1], and the pH of 0.40 M solutions of each of the following amines (the Kb values are found in Table 7.3). a. aniline b. methylamine

Chapter: 7 Problem: 7.84

Chemical Principles 8
Calculate the pH of a 0.20 M C2H5NH2 solution (Kb 5 5.6 3 1024).

Chapter: 7 Problem: 7.85

Chemical Principles 8
Calculate the pH of a 0.050 M (C2H5)2NH solution (Kb 5 1.3 3 1023).

Chapter: 7 Problem: 7.86

Chemical Principles 8
Codeine is a derivative of morphine that is used as an analgesic, narcotic, or antitussive. It was once commonly used in cough syrups but is now available only by prescription because of its addictive properties. The formula of codeine is C18H21NO3, and the pKb is 6.05. Calculate the pH of a 10.0-mL

Chapter: 7 Problem: 7.87

Chemical Principles 8
A codeine-containing cough syrup lists codeine sulfate as a major ingredient instead of codeine. The Merck Index gives C36H44N2O10S as the formula for codeine sulfate. Describe the composition of codeine sulfate (see Exercise 83). Why is codeine sulfate used instead of codeine?

Chapter: 7 Problem: 7.88

Chemical Principles 8
What is the percent ionization in each of the following solutions? a. 0.10 M NH3 c. 0.10 M CH3NH2 b. 0.010 M NH3

Chapter: 7 Problem: 7.89

Chemical Principles 8
Quinine (C20H24N2O2) is the most important alkaloid derived from cinchona bark. It is used as an antimalarial drug. For quinine pKb1 5 5.1 and pKb2 5 9.7 (pKb 5 2log Kb). Only 1.0 g of quinine will dissolve in 1900.0 mL of solution. Calculate the pH of a saturated aqueous solution of quinine. Conside

Chapter: 7 Problem: 7.90

Chemical Principles 8
The pH of a 0.016 M aqueous solution of p-toluidine (CH3C6H4NH2) is 8.60. Calculate Kb.

Chapter: 7 Problem: 7.91

Chemical Principles 8
Calculate the mass of HONH2 required to dissolve in enough water to make 250.0 mL of solution having a pH of 10.00 (Kb 5 1.1 3 1028).

Chapter: 7 Problem: 7.92

Chemical Principles 8
Phosphoric acid, H3PO4, is a triprotic acid. What are the three acids? Ka2 for phosphoric acid is 6.2 3 1028. What reaction refers to Ka2 ?

Chapter: 7 Problem: 7.93

Chemical Principles 8
Phosphoric acid is a common ingredient in traditional cola drinks. It is added to provide the drinks with a pleasantly tart taste. Assuming that in cola drinks the concentration of phosphoric acid is 0.007 M, calculate the pH in this solution.

Chapter: 7 Problem: 7.94

Chemical Principles 8
Write out the stepwise Ka reactions for citric acid (H3C6H5O7), a triprotic acid.

Chapter: 7 Problem: 7.95

Chemical Principles 8
Consider a 0.10 M H2CO3 solution and a 0.10 M H2SO4 solution. Without doing any detailed calculations, choose one of the following statements that best describes the [H1] of each solution and explain your answer. a. The [H1] is less than 0.10 M. b. The [H1] is 0.10 M. c. The [H1] is between 0.10 M an

Chapter: 7 Problem: 7.96

Chemical Principles 8
Arsenic acid (H3AsO4) is a triprotic acid with Ka1 5 5.5 3 1023, Ka2 5 1.7 3 1027, and Ka3 5 5.1 3 10212. Calculate [H1], [OH2], [H3AsO4], [H2AsO4 2], [HAsO4 22], and [AsO4 32] in a 0.20 M arsenic acid solution.

Chapter: 7 Problem: 7.97

Chemical Principles 8
Calculate [CO3 22] in a 0.010 M solution of CO2 in water (H2CO3). If all the CO3 22 in this solution comes from the reaction HCO3 2(aq) 34 H1(aq) 1 CO3 22(aq) what percentage of the H1 ions in the solution is a result of the dissociation of HCO3 2? When acid is added to a solution of sodium hydrogen

Chapter: 7 Problem: 7.98

Chemical Principles 8
A typical vitamin C tablet (containing pure ascorbic acid, H2C6H6O6) weighs 500. mg. One vitamin C tablet is dissolved in enough water to make 200.0 mL of solution. Calculate the pH of this solution. Ascorbic acid is a diprotic acid.

Chapter: 7 Problem: 7.99

Chemical Principles 8
Calculate the pH and [S22] in a 0.10 M H2S solution. Assume Ka1 5 1.0 3 1027; Ka2 5 1.0 3 10219.

Chapter: 7 Problem: 7.100

Chemical Principles 8
Calculate the pH of a 2.0 M solution of H2SO4.

Chapter: 7 Problem: 7.101

Chemical Principles 8
Calculate the pH of a 5.0 3 1023 M solution of H2SO4

Chapter: 7 Problem: 7.102

Chemical Principles 8
Give three example solutions that fit each of the following descriptions. a. a strong electrolyte solution that is very acidic b. a strong electrolyte solution that is slightly acidic c. a strong electrolyte solution that is very basic d. a strong electrolyte solution that is slightly basic e. a stro

Chapter: 7 Problem: 7.103

Chemical Principles 8
Derive an expression for the relationship between pKa and pKb for a conjugate acidbase pair.

Chapter: 7 Problem: 7.104

Chemical Principles 8
Rank the following 0.10 M solutions in order of increasing pH. a. HI, HF, NaF, NaI b. NH4Br, HBr, KBr, NH3 c. C6H5NH3NO3, NaNO3, NaOH, HOC6H5, KOC6H5, C6H5NH2, HNO3

Chapter: 7 Problem: 7.105

Chemical Principles 8
Arrange the following 0.10 M solutions in order from most acidic to most basic. CaBr2, KNO2, HClO4, HNO2, HONH3ClO4, and NH4NO2

Chapter: 7 Problem: 7.106

Chemical Principles 8
Are solutions of the following salts acidic, basic, or neutral? For those that are not neutral, explain why the solution is acidic or basic. The relevant Ka and Kb values are found in Tables 7.2, 7.3, and 7.4. a. Sr(NO3)2 d. NH4C2H3O2 b. C2H5NH3CN e. NaHCO3 c. C5H5NHF

Chapter: 7 Problem: 7.107

Chemical Principles 8
Is an aqueous solution of NaHSO4 acidic, basic, or neutral? What reaction occurs with water? Calculate the pH of a 0.10 M solution of NaHSO4.

Chapter: 7 Problem: 7.108

Chemical Principles 8
Determine [OH2], [H1], and the pH of each of the following solutions. a. 1.0 M KCI b. 1.0 M KF

Chapter: 7 Problem: 7.109

Chemical Principles 8
Calculate the concentrations of all species present in a 0.25 M solution of ethylammonium chloride (C2H5NH3Cl).

Chapter: 7 Problem: 7.110

Chemical Principles 8
A 0.050 M solution of the salt NaB has a pH of 9.00. Calculate the pH of a 0.010 M solution of HB.

Chapter: 7 Problem: 7.111

Chemical Principles 8
Calculate the pH of each of the following solutions. a. 0.10 M CH3NH3Cl b. 0.050 M NaCN

Chapter: 7 Problem: 7.112

Chemical Principles 8
Calculate the pH of each of the following solutions. a. 0.12 M KNO2 c. 0.40 M NH4ClO4 b. 0.45 M NaOCl

Chapter: 7 Problem: 7.113

Chemical Principles 8
Sodium azide (NaN3) is sometimes added to water to kill bacteria. Calculate the concentration of all species in a 0.010 M solution of NaN3. The Ka value for hydrazoic acid (HN3) is 1.9 3 1025

Chapter: 7 Problem: 7.114

Chemical Principles 8
An unknown salt is either NaCN, NaC2H3O2, NaF, NaCl, or NaOCl. When 0.100 mole of the salt is dissolved in 1.00 L of solution, the pH of the solution is 8.07. What is the identity of the salt?

Chapter: 7 Problem: 7.115

Chemical Principles 8
Consider a solution of an unknown salt having the general formula BHCl, where B is one of the weak bases in Table 7.3. A 0.10 M solution of the unknown salt has a pH of 5.82. What is the actual formula of the salt?

Chapter: 7 Problem: 7.116

Chemical Principles 8
Papaverine hydrochloride (abbreviated papH1Cl2; molar mass 5 378.85 g/mol) is a drug that belongs to a group of medicines called vasodilators, which cause blood vessels to expand, thereby increasing blood flow. This drug is the conjugate acid of the weak base papaverine (abbreviated pap; Kb 5 8.33 3

Chapter: 7 Problem: 7.117

Chemical Principles 8
The equilibrium constant Ka for the reaction Fe1H2O2 6 31 1aq2 1 H2O1l2m Fe1H2O2 5 1OH2 21 1aq2 1 H3O1 1aq2 is 6.0 3 1023. a. Calculate the pH of a 0.10-M solution of Fe(H2O)6 31. b. Will a 1.0-M solution of iron(II) nitrate have a higher or lower pH than a 1.0-M solution of iron(III) nitrate? Explai

Chapter: 7 Problem: 7.118

Chemical Principles 8
Calculate the pH of a 0.10 M solution of CoCl3. The Ka value for Co(H2O)6 31 is 1.0 3 1025

Chapter: 7 Problem: 7.119

Chemical Principles 8
Calculate the pH of a 0.200 M solution of C5H5NHF.

Chapter: 7 Problem: 7.120

Chemical Principles 8
Determine the pH of a 0.50 M solution of NH4OCl.

Chapter: 7 Problem: 7.121

Chemical Principles 8
Calculate the pH of a 0.10 M solution of sodium phosphate.

Chapter: 7 Problem: 7.122

Chemical Principles 8
Using the assumptions we ordinarily make in calculating the pH of an aqueous solution of a weak acid, calculate the pH of a 1.0 3 1026 M solution of hypobromous acid (HBrO, Ka 5 2 3 1029). What is wrong with your answer? Why is it wrong? Without trying to solve the problem, tell what has to be includ

Chapter: 7 Problem: 7.123

Chemical Principles 8
Calculate the pH of 4.0 3 1025 M phenol (Ka 5 1.6 3 10210).

Chapter: 7 Problem: 7.124

Chemical Principles 8
Calculate the pH of 5.0 3 1024 M HCN

Chapter: 7 Problem: 7.125

Chemical Principles 8
Calculate the pH of 5.0 3 1028 M HNO3.

Chapter: 7 Problem: 7.126

Chemical Principles 8
Calculate the pH of a 7.031027 M HCl solution.

Chapter: 7 Problem: 7.127

Chemical Principles 8
Calculate the pH of a 1.0 3 1027 M solution of NaOH in water.

Chapter: 7 Problem: 7.128

Chemical Principles 8
Calculate the value for the equilibrium constant for each of the following aqueous reactions. a. NH3 1 H3O1 34 NH4 1 1 H2O b. NO2 2 1 H3O1 34 HNO2 1 H2O c. NH4 1 1 CH3CO2 2 34 NH3 1 CH3CO2H d. H3O1 1 OH2 34 2H2O e. NH4 1 1 OH2 34 NH3 1 H2O f. HNO2 1 OH2 34 H2O 1 NO2 2

Chapter: 7 Problem: 7.129

Chemical Principles 8
A solution is prepared by adding 50.0 mL concentrated hydrochloric acid and 20.0 mL concentrated nitric acid to 300 mL water. More water is added until the final volume is 1.00 L. Calcuate [H1], [OH2], and the pH for this solution. [Hint: Concentrated HCl is 38% HCl (by mass) and has a density of 1.1

Chapter: 7 Problem: 7.130

Chemical Principles 8
A 10.0-mL sample of an HCl solution has a pH of 2.000. What volume of water must be added to change the pH to 4.000?

Chapter: 7 Problem: 7.131

Chemical Principles 8
Which of the following statements is(are) true? Correct the false statements. a. When a base is dissolved in water, the lowest possible pH of the solution is 7.0. b. When an acid is dissolved in water, the lowest possible pH is 0. c. A strong acid solution will have a lower pH than a weak acid soluti

Chapter: 7 Problem: 7.132

Chemical Principles 8
Hemoglobin (abbreviated Hb) is a protein that is responsible for the transport of oxygen in the blood of mammals. Each hemoglobin molecule contains four iron atoms that are the binding sites for O2 molecules. The oxygen binding is pH-dependent. The relevant equilibrium reaction is HbH4 41(aq) 1 4O2(g

Chapter: 7 Problem: 7.133

Chemical Principles 8
The pH of human blood is steady at a value of approximately 7.4 owing to the following equilbrium reactions: CO2(aq) 1 H2O(l) 34 H2CO3(aq) 34 HCO3 2(aq) 1 H1(aq) Acids formed during normal celluar respiration react with the HCO3 2 to form carbonic acid, which is in equilibrium with CO2(aq) and H2O(l)

Chapter: 7 Problem: 7.134

Chemical Principles 8
A solution is tested for pH and conductivity as pictured below: The solution contains one of the following substances: HCl, NaOH, NH4Cl, HCN, NH3, HF, or NaCN. If the solute concentration is about 1.0 M, what is the identity of the solute? 81982_ch07_0197-0240j.indd 7 9/18/15 1:48 PM Copyright 2017 C

Chapter: 7 Problem: 7.135

Chemical Principles 8
A 0.20 M sodium chlorobenzoate (NaC7H4ClO2) solution has a pH of 8.65. Calculate the pH of a 0.20 M chlorobenzoic acid (HC7H4ClO2) solution.

Chapter: 7 Problem: 7.136

Chemical Principles 8
A 0.25-g sample of lime (CaO) is dissolved in enough water to make 1500 mL of solution. Calculate the pH of the solution.

Chapter: 7 Problem: 7.137

Chemical Principles 8
Isocyanic acid (HNCO) can be prepared by heating sodium cyanate in the presence of solid oxalic acid according to the equation 2NaOCN(s) 1 H2C2O4(s) 88n 2HNCO(l) 1 Na2C2O4(s) Upon isolating pure HNCO(l), an aqueous solution of HNCO can be prepared by dissolving the liquid HNCO in water. What is the p

Chapter: 7 Problem: 7.138

Chemical Principles 8
Acrylic acid (CH2PCHCO2H) is a precursor for many important plastics. (Ka for acrylic acid is 5.6 3 1025.) a. Calculate the pH of a 0.10 M solution of acrylic acid. b. Calculate the percent dissociation of a 0.10 M solution of acrylic acid. c. Calculate the [H1] necessary to ensure that the percent d

Chapter: 7 Problem: 7.139

Chemical Principles 8
How many moles of HCl(g) must be added to 1.0 L of 2.0 M NaOH to achieve a pH of 0.00? (Neglect any volume changes.)

Chapter: 7 Problem: 7.140

Chemical Principles 8
Consider the following mathematical expressions. a. [H1] 5 [HA]0 b. [H1] 5 (Ka 3 [HA]0)1y2 c. [OH2] 5 2[B]0 d. [OH2] 5 (Kb 3 [B]0)1y

Chapter: 7 Problem: 7.141

Chemical Principles 8
Consider the following mathematical expressions. a. [H1] 5 [HA]0 b. [H1] 5 (Ka 3 [HA]0)1y2 c. [OH2] 5 2[B]0 d. [OH2] 5 (Kb 3 [B]0)1y2 For each expression, give three solutions where the mathematical expression would give a good approximation for the [H1] or [OH2]. [HA]0 and [B]0 represent initial con

Chapter: 7 Problem: 7.142

Chemical Principles 8
One mole of a weak acid HA was dissolved in 2.0 L of solution. After the system had come to equilibrium, the concentration of HA was found to be 0.45 M. Calculate Ka for HA.

Chapter: 7 Problem: 7.143

Chemical Principles 8
Calculate [OH2] in a solution obtained by adding 0.0100 mole of solid NaOH to 1.00 L of 15.0 M NH3.

Chapter: 7 Problem: 7.144

Chemical Principles 8
A solution of formic acid (HCOOH, Ka 5 1.8 3 1024) has a pH of 2.70. Calculate the initial concentration of formic acid in this solution.

Chapter: 7 Problem: 7.145

Chemical Principles 8
Will 0.10 M solutions of the following salts be acidic, basic, or neutral? See Appendix 5 for Ka values. a. ammonium bicarbonate b. sodium dihydrogen phosphate c. sodium hydrogen phosphate d. ammonium dihydrogen phosphate e. ammonium formate

Chapter: 7 Problem: 7.146

Chemical Principles 8
Citric acid (H3C6H5O7) is a triprotic acid with Ka1 5 8.4 3 1024, Ka2 5 1.8 3 1025, and Ka3 5 4.0 3 1026. Calculate the pH of 0.15 M citric acid.

Chapter: 7 Problem: 7.147

Chemical Principles 8
For solutions of the same concentration, as acid strength increases, indicate what happens to each of the following (increases, decreases, or doesnt change). a. [H1] d. pOH b. pH e. Ka c. [OH2]

Chapter: 7 Problem: 7.148

Chemical Principles 8
Complete the table for each of the following solutions: [H1] pH pOH [OH2] 0.0070 M HNO3 ______ ______ ______ ______ 3.0 M KOH ______ ______ ______ ____

Chapter: 7 Problem: 7.149

Chemical Principles 8
Consider a 0.60-M solution of HC3H5O3, lactic acid (Ka 5 1.4 3 1024). a. Which of the following are major species in the solution? i. HC3H5O3 ii. C3H5O3 2 iii. H1 iv. H2O v. OH2 b. Complete the following ICE table in terms of x, the amount (mol/L) of lactic acid that dissociates to reach equilibrium.

Chapter: 7 Problem: 7.150

Chemical Principles 8
Consider a 0.67-M solution of C2H5NH2 (Kb 5 5.6 3 1024). a. Which of the following are major species in the solution? i. C2H5NH2 ii. H1 iii. OH2 iv. H2O v. C2H5NH3 1 b. Calculate the pH of this solution

Chapter: 7 Problem: 7.151

Chemical Principles 8
Rank the following 0.10 M solutions in order of increasing pH. a. NH3 d. KCl b. KOH e. HCl c. HC2H3O2

Chapter: 7 Problem: 7.152

Chemical Principles 8
Consider 0.25 M solutions of the following salts: NaCl, RbOCl, KI, Ba(ClO4)2, and NH4NO3. For each salt, indicate whether the solution is acidic, basic, or neutral

Chapter: 7 Problem: 7.153

Chemical Principles 8
Calculate the pH of the following solutions: a. 1.2 M CaBr2 b. 0.84 M C6H5NH3NO3 (Kb for C6H5NH2 5 3.8 3 10210) c. 0.57 M KC7H5O2 (Ka for HC7H5O2 5 6.4 3 1025)

Chapter: 7 Problem: 7.154

Chemical Principles 8
Consider 0.10 M solutions of the following compounds: AlCl3, NaCN, KOH, CsClO4, and NaF. Place these solutions in order of increasing pH.

Chapter: 7 Problem: 7.155

Chemical Principles 8
Consider 1000. mL of a 1.00 3 1024 M solution of a certain acid HA that has a Ka value equal to 1.00 3 1024. Water was added or removed (by evaporation) so that a solution remains in which 35.0% of HA is dissociated at equilibrium. What is the final volume of the solution? Assume that HA is nonvolati

Chapter: 7 Problem: 7.156

Chemical Principles 8
A typical solution of baking soda (sodium bicarbonate, NaHCO3) has a pH that is independent of concentration. The pH of a solution of sodium bisulfate (NaHSO4) does depend on the concentration. a. Explain why the pH of a typical solution of sodium bicarbonate is concentration-independent, whereas the

Chapter: 7 Problem: 7.157

Chemical Principles 8
Calculate the mass of sodium hydroxide that must be added to 1.00 L of 1.00 M HC2H3O2 to double the pH of the solution (assume that the added NaOH does not change the volume of the solution).

Chapter: 7 Problem: 7.158

Chemical Principles 8
A certain acid, HA, has a vapor density of 5.11 g/L when in the gas phase at a temperature of 258C and a pressure of 1.00 atm. When 1.50 g of this acid is dissolved in enough water to make 100.0 mL of solution, the pH is found to be 1.80. Calculate Ka for HA.

Chapter: 7 Problem: 7.159

Chemical Principles 8
A 0.100 M solution of the salt BHX has a pH of 8.00, where B is a weak base and X2 is the anion of the weak acid HX. Calculate the Ka value for HX if the Kb value for B is 1.0 3 1023.

Chapter: 7 Problem: 7.160

Chemical Principles 8
A 0.100 M solution of the salt BHX has a pH of 8.00, where B is a weak base and X2 is the anion of the weak acid HX. Calculate the Ka value for HX if the Kb value for B is 1.0 3 1023.

Chapter: 7 Problem: 7.161

Chemical Principles 8
Determine the pH of a 0.100 M solution of (NH4)2C2O4.

Chapter: 7 Problem: 7.162

Chemical Principles 8
An aqueous solution contains a mixture of 0.0500 M HCOOH (Ka 5 1.77 3 1024) and 0.150 M CH3CH2COOH (Ka 5 1.34 3 1025). Calculate the pH of this solution.

Chapter: 7 Problem: 7.163

Chemical Principles 8
Consider 50.0 mL of a solution of weak acid HA (Ka 5 1.00 3 1026), which has a pH of 4.000. What volume of water must be added to make the pH 5 5.000?

Chapter: 7 Problem: 7.164

Chemical Principles 8
A 50.00-mL solution of a weak acid HA (Ka 5 5.00 3 10210) in water has a pH 5 5.650. Calculate the amount of water that must be added to reach a pH value of 6.650

Chapter: 7 Problem: 7.165

Chemical Principles 8
Calculate the pH of a solution initially with 0.10 M NaHSO4 and 0.10 M NH3.

Chapter: 7 Problem: 7.166

Chemical Principles 8
A chemist dissolves 0.135 mole of CO2(g) in 2.50 L of 0.105 M Na2CO3. Calculate the pH of the resulting solution

Chapter: 7 Problem: 7.167

Chemical Principles 8
Derive an equation to solve for the pH for a dilute weak base in which water is a significant contributor to the pH. Use this formula to calculate the pH of a 100.0-mL sample of 2.0 3 1025 M B (where B is a weak base with a Kb value of 6.1 3 10211)

Chapter: 7 Problem: 7.168

Chemical Principles 8
Calculate the pH of 6.0 3 1024 M NaNO2.

Chapter: 7 Problem: 7.169

Chemical Principles 8
Calculate the resulting pH when 1.00 L of 1.00 M H2SO4 is added to a tank containing 1.00 3 107 L of pure water.

Chapter: 7 Problem: 7.170

Chemical Principles 8
Calculate the pH of a solution prepared by mixing equal volumes of 1.0 3 1024 M NH3 and 1.0 3 1024 M HCl.

Chapter: 7 Problem: 7.171

Chemical Principles 8
Calculate [OH2] in a 3.0 3 1027 M solution of Ca(OH)2.

Chapter: 7 Problem: 7.172

Chemical Principles 8
Mix equal volumes of one solution from Group I with one solution from Group II to achieve the results below. Calculate the pH of each solution. Group I: 0.20 M NH4Cl, 0.20 M HCl, 0.20 M C6H5NH3Cl, 0.20 M (C2H5)3NHCl Group II: 0.20 M KOI, 0.20 M NaCN, 0.20 M KOCl, 0.20 M NaNO2 a. the solution with the

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