Ch 18 smartbook
How does a conjugate acid differ from its conjugate base? Select all that apply.
-The conjugate acid of a neutral base will have a charge of +1. -A conjugate base may be positively charged, neutral, or negatively charged. -The conjugate acid has one more H than its conjugate base
For solutions with the same initial concentration of acid HA, the smaller the value of Ka, the _____ the % dissociation and thus the _____ the acid.
lower, weaker
The two general types of weak base include molecules that contain one or more _________atoms and the conjugate bases of weak _______ .
nitrogen, acids
Which of the following compounds can be classified as bases according to the Arrhenius definition? Select all that apply.
NaOH, Ba(OH)2
______ metal ions are acidic in aqueous solution because their hydrated form can transfer an H+ to water.
Small, highly charged
Which of the following options correctly describe the structural characteristics of strong and weak bases? Select all that apply. Multiple select question.
Soluble hydroxides are strong bases.Compounds that contain electron-rich N are weak bases.Amines such as CH3CH2NH2 are weak bases.
The pH of a solution is a logarithmic value. This means that ______. Multiple choice question.
only digits after the decimal point of significant
The quantity -log[H3O+] is called __________ the of a solution. Listen to the complete question
pH
Calculate the pH and [OH-] of a solution of a 1.5 M solution of HCl.
pH = -0.18 [OH-] = 6.7*10^-15
In a Bronsted-Lowry acid-base reaction, equilibrium will favor the _____ if the reacting acid and base are strong. The reaction will always favor the formation of the _____ acid and base.
products, weaker
Acid dissociation is represented by the general equation HA + H2O (l) ⇌ H3O+ (aq) + A- (aq). For a strong acid the equilibrium lies far to the _____ and [H3O+] is much _____ than [HA]. For a weak acid, on the other hand, the equilibrium lies far to the _____ and [H3O+] is much _____ than [HA]. Multiple choice question.
right; higher; left; lower
A salt consisting of the anion of a _____ acid and the cation of a _____ base yields an acidic solution. Multiple choice question.
strong, weak
The direction of an acid-base equilibrium depends on the relative strengths of the acids and bases involved. Since strong acids and strong bases readily accept and donate protons, the equilibrium will always favor the reaction of the _____ acid and base and the formation of the _____ acid and base. Multiple choice question.
stronger, weaker
A(n) ________ acid is one that dissociates only slightly in water, whereas a(n) _________ acid dissociates completely into ions
weak, strong
HCN has a Ka value of 6.3 x 10-10 while acetic acid has a Ka value of 1.8 x 10-5. HCN is a _____ acid than acetic acid and will therefore have a _____ pKa value.
weaker, higher
H2S is a _____ acid than HCl because S is _____ electronegative than Cl, while HBr is a _____ acid than HCl because the H-Cl bond is shorter and has _____ strength than the H-Br bond.
weaker; less; stronger; greater
Which of the following anions will produce a neutral solution in water? Select all that apply, and assume that any associated cations do not affect the pH.
- I- - Cl- - NO3-
Select all the statements that correctly describe the aqueous solution of a metal cation. Multiple select question.
-A metal cation can withdraw electron density from the O-H bonds of H2O molecules, releasing H+ ions. -A solution containing small, highly charged metal cations will be acidic.
Which of the following statements describe the behavior of strong and weak acids (general formula HA) in aqueous solution? Select all that apply.
-A weak acid is a weak electrolyte. -The solution of a strong acid will have extremely few to no undissociated HA molecules
Match each type of substance with the correct description of its behavior according to the Arrhenius acid-base definition.
-An acid contains one or more: hydrogen atoms in its formula. -A base contains the unit: OH in its formula. -H3O+ ions are produced: an acid in an aqueous solution. -OH- ions are produced: by a base in an aqueous solution.
Match each acid correctly to the number of ionizable protons. Instructions
-H3AsO4: 3 -H2S:2 -HCOOH: 1
Match each acid correctly to the number of ionizable protons.
-H3PO4: 3 -H2CO3: 2 -CH3COOH: 1
The aqueous solutions of a strong acid and a weak acid are compared. Match each acid with the species that is/are present in the greatest concentration in the final solution. Note that the generic formula HA is used for each acid and A- for the conjugate base in both cases.
-Strong acid: [H3O+], A- -Weak acid: HA
Select the correct statements describing a solution containing a salt composed of the cation of a strong base and the anion of a polyprotic acid. Select all that apply
-The anion will hydrolyze to produce either H3O+ or OH- ions depending on the relative values of Ka and Kb of the anion -The cation has no impact on the pH of the solution.
Calculate the pH and [H3O+] of a 0.080 M solution of NaOH.
-[H3O+] = 1.3 x 10-13 M -pH = 12.90
A Bronsted-Lowry base is a proton _____. A Bronsted-Lowry base must contain an available ____ pair of ________ in its formula in order to form a(n) _______ bond to the H+.
Acceptor, lone, electrons, covalent
Which of the following statements does NOT describe a type of weak acid?
All hydrohalic acids in Period 3 or below
Which of the following species is present in the greatest concentration in a 1.0 M solution of CH3COOH? Multiple choice question.
CH3COOH
Rank the following compounds in order of decreasing acid strength (strongest at the top to weakest at the bottom of the list). Instructions
H2SO4 H2SO3 H2SeO
Arrange the following acids in order of greatest (at the top of the list) to least (at the bottom of the list) amount of H3O+ produced in solution. All the acids have the same initial concentration of HA
HClO2 HF HClO HCN
select all the weak acids
HF, HCN, CH3CH2COOH
Which of the following monoprotic acids would give a solution with the lowest pH at the same molarity?
HSO4- (pKa = 1.99)
Select all the expressions that correctly express the relationship between Ka and Kb for a conjugate acid-base pair.
Ka = Kw/Kb Ka x Kb = Kw
In order to determine whether a solution of NH4C2H3O2 is acidic, basic, or neutral, what two values could be compared? Multiple select question.
Ka of NH4+ Kb of CH3COO-
Which of the following expressions correctly represents Kb for a weak base of general formula B?
Kb = [BH+][OH−]/[B]
Match the relationship between Ka and pKa values correctly.
Large Ka value: Low pKa value Small Ka value: High pKa value
select all the strong bases from the list:
LiOH, Na2O, Ca(OH)2
Which of the following factors will affect the relative strength of oxoacids? Select all that apply.
The electronegativity of the central nonmetal atomThe number of O atoms attached to the central nonmetal atom
Which of the following statements correctly describe a 1.0 M solution of KCN? Select all that apply.
The solution contains a significant concentration of the weak base CN-.The solution is basic
A salt consisting of the anion of a weak _____ and the cation of a strong _____ yields a basic solution.
acid, base
A salt consisting of a small, highly charged metal cation and the anion of a strong acid yields a(n) _____ solution.
acidic
[H3O+] compared to [OH-] in an acidic, basic, neutral solution
acidic solution: [H3O+] > [OH-]basic solution: [OH-] > [H3O+]neutral solution: [H3O+] = [OH-]
A particular salt contains both an acidic cation and a basic anion. If the Ka of the cation is greater than the Kb of the anion, a solution of the salt will be ______. If the Ka of the cation is less than the Kb of the anion, a solution of the salt will be ______
acidic, basic
A salt consisting of the _____ of a strong acid and the _____ of a strong base yields a neutral solution.
anion, cation
An acid donates a proton to form its conjugate _____ which therefor has one less ______ atom and one more ______ charge than its acid
base, hydrogen, negative
The strength of a weak base is indicated by its _________ -ionization constant Kb. The greater the value of Kb, the ________the base.
base, stronger
Given the ion-product constant for water Kw = [H3O+][OH-], as the concentration of hydronium increases the concentration of hydroxide _____.
decreases
A Bronsted-Lowry acid is a proton _____ and must therefore contain at least one ionizable _____ atom in its formula
donor, hydrogen
Select all the factors that affect the ease with which a proton is released from a nonmetal hydride (represented by the general formula E-H.)
-The electronegativity of the central atom (E) -The strength of the E-H bond
Select the correct descriptions of the leveling (limiting) effect of water on strong acids and strong bases. Select all that apply.
-The strongest acid in an aqueous solution is the hydronium ion. -A strong acid will cease to exist in aqueous solutions because water will readily accept its proton to form hydronium ions
Which of the following options correctly describe the constant Ka?
-[H2O] is not included in the Ka expression for a particular acid -Ka is the acid-dissociation constant.
Which of the following statements correctly describes the behavior of strong acids, HA, in aqueous solution?
-[H3O+] = [A-] ≈ [HA]init -Strong acid molecules are not present in aqueous solutions. -A strong acid dissociates completely into ions in water.
In order to determine the overall acidity of a 0.1 M solution of NaHCO3, the ________ and ________ values for HCO3- must be compared. Ignore the use of any superscripts or subscripts in your answers.
-pKa -pKb
Which of the following solutions of HCN will have the greatest percent dissociation?
0.00010 M
Arrange the following compounds in order of increasing acid strength (weakest at the top to strongest at the bottom of the list).
1, H20 2. HF 3. HBr
A 0.15 M solution of butanoic acid, CH3CH2CH2COOH, contains 1.51 x 10-3 M H3O+. What is the Ka of butanoic acid? Multiple choice question.
1.5 x 10-5
Which of the options given expresses the solution to the following calculation to the correct number of significant figures? pH = -log(1.12 x 10-12)
11.951
Nitrous acid, HNO2, has a Ka of 7.1 x 10-4. What is the [H3O+] in a 0.60 M solution of HNO2?
2.1 x 10-2 M
An acid has a Ka of 1.34 × 10-6. What is the pH of a 0.509 M solution?
3.08
What is the Ka of an acid if a 0.500 M solution contains 1.70 x 10-4 M H3O+?
5.8 x 10-8
The pH of a solution is a measure of its _____ concentration.
H3O+
Which one of the following 0.1 M salt solutions will be basic? Multiple choice question.
NaCN
True or false: For any acid-base reaction, Ka x Kb = Kw for the reacting acid and base.
false
The stronger the acid, the _____ the [H3O+] at equilibrium and the _____ the value of Ka.
higher, larger
As the initial concentration of a weak acid decreases, the percent dissociation of the acid _____.
increase
Oxoacids have the general formula illustrated, where the number of bonds to the central element E can vary. For the same element E, acid strength will _____ as the number of O atoms increases. For the same number of O atoms, acid strength increases as the _____ of element E increases
increase, electronegativity
As the initial concentration of a weak acid decreases, the percent dissociation of the acid _____. Multiple choice question.
increases
Since pK = -logK, a low pK value corresponds to a _____ K value. A strong acid will have a _____ Ka value and a _____ pKa value
large; large; low