Deck 9: Acids, Bases, and Buffers in the Body

Question 1

A Brønsted-Lowry acid is defined as a substance which:

A)increases [H⁺] when placed in water
B)decreases [H⁺] when placed in water
C)acts as a proton acceptor in any system
D)acts as a proton donor in any system

Answer 1

acts as a proton donor in any system

Question 2

A Brønsted-Lowry base is defined as a substance which:

A)acts as proton acceptor in any system
B)acts as proton donor in any system
C)decreases [H⁺] when placed in water
D)increases [H⁺] when placed in water

Answer 2

acts as proton acceptor in any system

Question 3

An Arrhenius acid is defined as a substance which:

A)acts as proton acceptor in any system
B)acts as proton donor in any system
C)decreases [H⁺] when placed in water
D)increases [H⁺] when placed in water

Answer 3

increases [H⁺] when placed in water

Question 4

Which of the following properties is not characteristic of an acid?

A)Has a sour taste
B)Produces H+ in water
C)Has a slippery feel
D)Is neutralized by a base

Question 5

Which of the following properties is not characteristic of a base?

A)Has a bitter taste
B)Produces H+ in water
C)Has a slippery feel
D)Is neutralized by an acid

Question 6

In the following equation which is the proton donor and which is the proton acceptor?
CO₃^2- (aq)+ H₂O (l)? HCO₃^- (aq)+ OH^- (aq)

A)Donor: CO₃^2-; acceptor: H₂O
B)Donor: H₂O; acceptor: CO₃^2-
C)Donor: HCO₃^-; acceptor: OH^-
D)Donor: OH^-; acceptor: HCO₃^-

Question 7

Which of the following cannot act as a Brønsted-Lowry acid?

A)HSO₄^-
B)H₂O
C)CO₃^2-
D)HS^-

Question 8

In the following equation identify the Brønsted-Lowry acid and base, respectively:
NH₃ + HCN ? NH₄⁺ + CN^-

A)NH₃ and HCN
B)HCN and NH₃
C)NH₄⁺ and CN^-
D)NH₃ and NH₄⁺

Question 9

Which of the following is not a strong acid?

A)HCl (aq)
B)HNO₃
C)HC₂H₃O₂
D)HClO₄

Question 10

Which of the following is not a strong base?

A)NaOH
B)Al(OH)₃
C)KOH
D)Ca(OH)₂

Question 11

Which of the following is a strong base?

A)NH₃
B)CH₃OH
C)Ba(OH)₂
D)CH₃COOH

Question 12

Which of the following is a weak acid?

A)H₃PO₄
B)HNO₃
C)NH₃
D)OH^-

Question 13

Which of the following is a correct balanced equation for the neutralization reaction that occurs between Al(OH)₃ and HCl (aq)?

A)Al(OH)₃ + 3 HCl (aq)? AlCl₃ + 3 H₂O
B)Al(OH)₃ + HCl (aq)? AlCl₃ + H₂O
C)Al(OH)₃ + 3 HCl (aq)? AlCl₃ + H⁺ + OH^-
D)Al³⁺ + OH^- + H⁺ + Cl^- ? AlCl₃ + H₂O

Question 14

The name of the acid HClO is:

A)hypochlorous acid
B)chlorous acid
C)chloric acid
D)perchloric acid

Question 15

Which of the following compounds will form CO₂ and H₂O when it reacts with an acid?

A)Mg(OH)₂
B)CaCO₃
C)NH₃
D)NaC₂H₃O₂

Question 16

Given the following reaction, the equilibrium expression will be:
4 CuO (s)+ CH₄ (g)? CO₂ (g)+ 4 Cu (s)+ 2 H₂O (g)

A)[CuO]/[Cu]
B)[CuO]⁴/[Cu]⁴
C)[Cu]⁴/[CuO]⁴
D)[CO₂][H₂O]²/[CH₄]

Question 17

The following reaction is exothermic. Which of the following will drive the reaction to the right (towards products)?
CH₄ (g)+ 2 O₂ (g)? CO₂ (g)+ 2 H₂O (g)

A)A decrease in temperature
B)An increase in temperature
C)The removal of CH₄
D)The addition of CO₂

Question 18

Consider the following system at equilibrium: SO₂Cl₂₍g)? SO₂₍g)+ Cl₂₍g)
Identify which combination of the following changes will shift the equilibrium to the product side.
I. Addition of SO₂Cl₂
II. Addition of SO₂
III. Removal of SO₂Cl₂
IV. Removal of Cl₂

A)I + II
B)III + IV
C)I + IV
D)II + III

Question 19

Consider the following system at equilibrium: N₂ (g)+ 3 H₂ (g)? 2 NH₃ (g)+ 92.94 kJ
Which of the following changes will shift the equilibrium to the right?
1) Increasing the temperature
2) Decreasing the temperature
3) Removing some NH₃
4) Adding some NH₃
5) Removing some N₂
6) Adding some N₂

A)2, 3, 6
B)1, 4, 5
C)1, 3, 6
D)2, 4, 6

Question 20

When a system is at equilibrium:

A)the reaction rate of the forward reaction is equal to the rate of the reverse
B)the reaction rate of the reverse reaction is small compared to forward
C)the reaction rate of the forward reaction is small compared to the reverse
D)the amount of product and reactant is exactly equal

Question 21

Given the following reaction,write the equilibrium expression:
C (s)+ 2 H₂ (g)? CH₄ (g)

A)[CH₄]/[C] [H₂]²
B)[C][H₂]
C)[CH₄]/[H₂]²
D)[H₂]²[C]/[CH₄]

Question 22

What is the conjugate base of OH^-?

A)H₂O
B)O^-
C)O₂
D)O^-2

Question 23

What is the conjugate acid of HS^-?

A)S^2-
B)H₂S
C)HS^-
D)S^-

Question 24

Which of the following does not represent a conjugate acid-base pair?

A)H₃O⁺/H₂O
B)HCN/CN^-
C)HCl/Cl^-
D)HC₂H₃O₂/OH^-

Question 25

Which of the following does not represent a conjugate acid-base pair?

A)HCO₃^-/CO₃^2-
B)H₃PO₄/HPO₄^2-
C)OH^-/O^2-
D)NH₄⁺/NH₃

Question 26

Which is the correct combination of Brønsted-Lowry bases in the following equilibrium?
H₂PO₄^- + H₂O ? H₃PO₄ + OH^-

A)H₂PO₄^-+ OH^-
B)H₂PO₄^-+ H₃PO₄
C)H₂O + H₃PO₄
D)H₂O + OH^-

Question 27

Calculate the pH of 0.00756 M HNO₃.

A)11.879
B)7)091
C)2)121
D)12.947

Question 28

In an acidic solution, pH is ________ and [H₃O⁺] is ________.

A)= 7, 1 × 10^-7 M
B)> 7, < 1 × 10^-7 M
C)< 7, > 1 × 10^-7 M
D)< 7, < 1 × 10^-7 M

Question 29

In a basic solution, pH is ________ and [H₃O⁺] is ________.

A)= 7, 1 × 10^-7 M
B)> 7, < 1 × 10^-7 M
C)< 7, > 1 × 10^-7 M
D)< 7, < 1 × 10^-7 M

Question 30

What is the pH of a solution that has a [H₃O⁺] = 1.2 × 10^-3?

A)1)20
B)2)92
C)11.08
D)12.80

Question 31

Calculate the [H₃O⁺] and the pH of a 0.021 M HNO₃ solution.

A)4)8 × 10^-13 M and 12.32
B)4)8 × 10^-13 M and -12.32
C)0)021 M and 1.68
D)0)021 M and -1.68

Question 32

What is the [H₃O⁺] concentration of a solution that has a pH = 2.34?

A)2)3 × 10^-3 M
B)4)6 × 10^-3 M
C)2)2 × 10^-12 M
D)1)2 × 10¹ M

Question 33

What is the [H₃O⁺] concentration of a solution that has a pH = 11.61?

A)1)2 × 10¹ M
B)1)0 × 10^-14 M
C)2)5 × 10^-12 M
D)4)1 × 10¹¹ M

Question 34

Which of the following pH's represents a neutral solution?

A)5)40
B)7)00
C)8)65
D)1)25

Question 35

Which of the following is the strongest weak acid?

A)H₂PO₄^- pKa = 7.18
B)NH₄⁺ pKa = 9.20
C)HC₂H₃O₂ pKa = 4.76
D)HCO₃^- pKa = 10.32

Question 36

Which of the following is the weakest acid?

A)H₂PO₄^- pKa = 7.18
B)NH₄⁺ pKa = 9.20
C)HC₂H₃O₂ pKa = 4.76
D)HCO₃^- pKa = 10.32

Question 37

Consider the weak acid HCO₃^- whose pKa = 10.32, which form will predominate when the pH of the solution is 8.5?

A)HCO₃^-
B)CO₃^2-
C)H₂CO₃
D)All of these

Question 38

Consider the weak acid HCO₃^- whose pKa = 10.32, which form will predominate when the pH of the solution is 12.00?

A)HCO₃^-
B)CO₃^2-
C)H₂CO₃
D)All of these

Question 39

Which of the following represents the zwitterions form of the amino acid valine?

A)
B)
C)
D)

Question 40

The isoelectric point of an amino acid is defined as:

A)the pH at which the amino acid exits in the zwitterion form
B)the pH at which it exists in the basic form
C)the pH at which it exists in the acidic form
D)the pH equals the pKa

Question 41

If the pI for a particular amino acid is 7.5, at which pH will the net charge on the molecule be zero?

A)2)5
B)5)0
C)7)5
D)10.0

Question 42

Which of the following substances, when added to a solution of nitrous acid (HNO₂), could be used to prepare a buffer solution?

A)HCl
B)NaCl
C)HC₂H₃O₂
D)NaNO₂

Question 43

Which of the following buffers is the one that is mainly contained in our blood?

A)HC₂H₃O₂/C₂H₃O₂^-
B)NH₄⁺/NH₃
C)H₂CO₃/HCO₃^-
D)HPO₄^2-/PO₄^3-

Question 44

When a person hyperventilates the condition is known as:

A)respiratory acidosis
B)respiratory alkalosis
C)metabolic acidosis
D)metabolic alkalosis

Question 45

When a person does excess vomiting the condition the blood develops is called:

A)respiratory acidosis
B)respiratory alkalosis
C)metabolic acidosis
D)metabolic alkalosis

Question 46

When a diabetic does not have enough glucose in their blood it develops a condition called:

A)respiratory acidosis
B)respiratory alkalosis
C)metabolic acidosis
D)metabolic alkalosis

Question 47

An Arrhenius acid produces ________ ions in aqueous solution.

Question 48

An Arrhenius base produces ________ ions in aqueous solution.

Question 49

A Brønsted and Lowry acid ________ protons.

Question 50

A Brønsted and Lowry base ________ protons.

Question 51

Identify the acid (A), base (B), conjugate acid (CA)and conjugate base (CB)in each of the following reactions:

A)HSO₄^- (aq)+ ClO^-(aq)⇔ HClO (aq)+ SO₄^2- (aq)
B)H₂C₂O₄ (aq)+ NH₃ (aq)⇔ HC₂O₄^- (aq)+ NH₄⁺
C)CN^- (aq)+ HC₂H₃O₂ (aq)⇔ HCN (aq)+ C₂H₃O₂^-
D)H₂S (aq)+ NH₃ (aq)⇔ HS^- (aq)+ NH₄⁺ (aq)

Question 52

Identify the weak acids in the following list: HNO₃, H₂SO₃, HF, HCl, H₃PO₄, H₂SO₄

Question 53

Write the equation that shows how the weak base NH₃ produces OH^- ions in water.

Question 54

Insert the coefficients to balance this equation.
________ Na₂CO₃(s)+ ________ HNO₃(aq)→ ________ NaNO₃(aq)+ ________ H₂O(l)+ ________ CO₂(g)

Question 55

The general expression for the equilibrium constant K is given by:

Question 56

A large value of K means that the equilibrium greatly favors the ________, and a small value of K means that the equilibrium greatly favors the ________.

Question 57

Write the expression for K for the following equilibrium:
4 HCl(aq)+ MnO₂(s)⇔ MnCl₂(aq)+ Cl₂(g)+ 2H₂O(l)

Question 58

According to Le Chatelier's principle, addition of a reactant shifts the equilibrium to the ________, while addition of a product shifts the equilibrium to the ________.

Question 59

In the Haber process, in which N₂ and H₂ are converted into NH₃, reduction of the volume at constant temperature causes the amount of NH₃ to ________.

Question 60

The strength of an acid increases as the value of Ka ________.

Question 61

Use the values of Ka in Table 9.5 in the text to identify the stronger acid in each of these pairs:

A)HF and HNO₂
B)NH₄⁺ and HCO₃^-
C)HCOOH and CH₃COOH

Question 62

Write the definition of pH.

Question 63

As the pH value increases, [H₃O⁺] ________.

Question 64

Indicate whether the following solutions are acidic, basic or neutral. For each concentration calculate the pH of the solution.

A)[H⁺] = 1.1 × 10^-3 M
B)[H⁺] = 6.0 × 10^-11 M

Question 65

Calculate the [H₃O⁺] concentrations in solutions with the following pH values: 2.37, 5.65, 8.92, 12.48

Question 66

Write the definition of pKa.

Question 67

As pKa increases, the strength of the acid ________.

Question 68

In a solution that has a pH > pKa, the concentration of the acid form is ________ than that of the conjugate base.

Question 69

The form of an amino acid where the amine group is protonated and the carboxylic group exists an anion is called a ________.

Question 70

The isoelectric point occurs when the pH of the solution of the amino acid is ________ between the pKa value for the protonated amine and the pKa value for the carboxylic acid.

Question 71

A Brønsted and Lowry acid accepts protons.

Question 72

An Arrhenius acid accepts protons.

Question 73

In the equilibrium HPO₄^2-(aq)+ H₂O(l)? H₂PO₄^-(aq)+ OH^-(aq), H₂O is a Brønsted and Lowry acid.

Question 74

The equilibrium constant expression for the reaction, 2 HgO(s)? 2 Hg(l)+ O₂(g)is K = .

Question 75

An equilibrium with a large value of K favors the reactants.

Question 76

The strength of an acid increases as Ka increases.

Question 77

When CO₂ is bubbled into water at pH 7, the pH decreases.

Question 78

The strength of an acid increases as pKa increases.

Question 79

A 1.0 M solution of an acid with a pKa of 5.65 has higher [H₃O⁺] than a 1.0 M solution of an acid with pH of 6.75.

Question 80

When the pH of a solution of a weak acid is less than the pKa, the concentration of the acid form is greater than that of the conjugate base.