chem unit 3
A salt consisting of the _____ of a strong acid and the _____ of a strong base yields a neutral solution.
anion; cation
A salt in which the anion is the conjugate _____ of a weak _____ will produce a basic solution. (Assume that the cation does not hydrolyze.)
base, acid
An acid donates a proton to form its conjugate ___, which therefore has one less___ atom and one more___ charge than its acid.
base; H; negative
Select the correct expression for the equilibrium constant for the overall reaction (Koverall) that results when two chemical equations are added.
Koverall = K1 × K2
Match each species to the correct Lewis acid-base definition.
Lewis base-> Electron pair donor Lewis acid-> Electron pair acceptor
A compound that contains one or more ionizable___ atoms as well as one or more available ___electron pairs can act as either an acid or a base, depending on the reaction.
hydrogen; lone
The concentrations of ______ do not appear in reaction quotient (Qc) or equilibrium constant (Kc) expressions? Select all that apply.
pure solids; pure liquids
When Q < K, the reaction will proceed such that the amounts of the _____ decrease and the amounts of the _____ increase.
reactants, products
Le Chatelier's principle states that when a stress is applied to a system at equilibrium, the system will respond by shifting in a direction that ___ the effect of the stress. The system will therefore establish a new ____position.
reduces; equilibrium
Rank the following 0.1 M salt solutions in order of increasing pH (lowest pH at the top of the list).
- NaHSO4 -NH4NO3 -NaHCO3 -Na2CO3
Given the balanced chemical equation shown below, calculate the value of Δn. 2PbO (s) + O2 (g) ⇌ 2PbO2 (s)
-1
The pH of a salt solution containing a small, highly charged metal cation is influenced by the hydrolysis reaction of the metal ion. Which of the following statements correctly explain the hydrolysis reaction of these metal cations? Select all that apply.
-A hydrated metal ion produces an acidic solution because the metal ion withdraws electron density from the O-H bond, facilitating loss of H+. -Small, highly charged metal cations accept electron pairs from water molecules and form hydrated ions.
The magnitude of K correlates with the sign of ΔGo. Select all the correct statements that apply about this relationship.
-A reaction with a positive ΔGo will result in an equilibrium mixture composed primarily of reactants. -A reaction with a very large K value has a negative ΔGo.
You are given Kc as well as the initial reactant concentrations for a chemical system at a particular temperature. Select any steps for determining the equilibrium concentrations of the reactants and products that are not correct.
-For each species in the equilibrium, multiply the stoichiometric coefficient by x to obtain the equilibrium concentration in terms of x. -Use the initial concentrations given to calculate the value of Kc.
A buffer used in food products is the benzoic acid/benzoate buffer, which has a pKa = 4.19. If you need to maintain a pH of 3.50 using this buffer system, what concentration of benzoate ion would you need if you have 0.05 M benzoic acid?
0.01 M benzoate ion
The [OH-] of a 0.010 M Ba(OH)2 solution is _____ M and the pOH is equal to _____.
0.020, 1.70
In order for a solution of a weak acid and its conjugate base to be considered a buffer, the ratio of base concentration to acid concentration must be within the range ______.
0.1 < [base]/[acid] < 10
Which of the following can NOT be used as an acid-base buffer solution? Select all that apply.
0.3 M HCl and 0.3 M NaOH 0.5 M HNO3 and 0.5 M NaNO3
The Haber process for the production of ammonia is N2(g) + 3H2(g) ⇌ 2NH3(g) and Kc = 0.115 at 1000°C. What is the value of Kc' for the reaction 1/2 N2(g) + 3/2H2(g) ⇌ NH3(g)?
0.339 Reason: Since the reaction is one-half times the first reaction, the new equilibrium expression is [NH3]/[N2]1/2[H2]3/2[NH3][N2]1/2[H2]3/2 and the value of Kc' = (Kc)1/2 = Kc⎯⎯⎯⎯√Kc = 0.115⎯⎯⎯⎯⎯⎯⎯⎯⎯√0.115 = 0.339
For the chemical system 2NO2 (g) ⇌ 2NO (g) + O2 (g), the equilibrium constant K1 = 1.1 x 10-5. What is the value of K for the reaction 6NO2 (g) ⇌ 6NO (g) + 3O2 (g)?
1.3 x 10-15
In order for a solution of a weak acid and its conjugate base to be an effective buffer, the ratio of weak acid to weak base (or vice versa) must be ______-fold or less.
10
Calculate the Kb value for the acetate ion (CH3COO-) if the Ka value for acetic acid (CH3COOH) is 1.8 x 10-5.
5.6 × 10-10
For the chemical system 2NO2 (g) ⇌ 2 NO (g) + O2 (g), the equilibrium constant K = 1.1 × 10-5. What is the value of K for the reaction 2NO (g) + O2 (g) ⇌ 2NO2 (g)?
9.1 × 104 Reason: K' = 1/K = 1/1.1×10−5
A buffer is made up using 2.5 L of 0.25 M sodium phenolate (C6H5ONa) and solid phenol (C6H5OH; pKa = 10.0). The desired buffer pH is 9.82. Which of the following options correctly show the calculations required to calculate the mass of phenol needed? Select all that apply.
9.82 = 10.00 + log0.25/5[phenol] Mass of phenol required = 2.5 L × 0.38mol/1L × 94.1/1mol [phenol] = 0.25/10−0.18
Which of the following options correctly describes the function of an acid-base buffer?
A buffer minimizes changes in pH when acid or base is added to the solution.
Match the relative concentrations of hydronium and hydroxide with the type of solution.
Acidic solution [H3O+] > [OH-] Basic solution [OH-] > [H3O+] Neutral solution[H3O+] = [OH-]
Predict which of the following species would act as an amphoteric compound, that is, as both a Bronsted acid and a Bronsted base? Select all that apply.
H2PO4- HCO3- H2O
Which of the following statements correctly describe amphoteric hydroxides? Select all that apply.
Amphoteric hydroxides react with both acids and bases. Al(OH)3 is an amphoteric hydroxide.
The product of a Lewis acid-base reaction is (CH3)2OBF3. Select all the statements that correctly describe this reaction.
BF3 accepts an electron pair in this reaction. An empty 2p orbital on B accepts an electron pair from O
Which of the following statements correctly describe the acid-base properties of a 0.10-M solution of ammonium cyanide (NH4CN)? Select all that apply. Ka of NH4+ = 5.6 x 10-10 and Kb of CN- = 1.8 x 10-5.
Both NH4+ and CN- will hydrolyze (react with water) in aqueous solution. CN- will behave as a base when it reacts with water. The solution will be basic.
Rank the following carboxylic acids in order of increasing acid strength (weakest at the top to strongest at the bottom of the list). Instructions
CH3COOH BrCH2COOH ClCH2COOH Cl3CCOOH
Which of the following statements correctly describe carboxylic acids, represented by the general formula RCOOH? Select all that apply.
Carboxylic acids are organic acids represented by the general formula RCOOH. As R changes, the strength of the acid changes. Carboxylic acids are weaker acids than hydrohalic acids such as HCl.
Which of the following oxides will NOT produce a basic solution in water?
Cl2O
Rank these bases in order of increasing strength, placing the strongest base at the bottom of the list.
Cl3CCOO-- Cl2CHCOO-- ClCH2COO-- CH3COO--
Which of the following species are Lewis acids? Select all that apply.
Cu2+ SO3 BF3
Which of the protons depicted in the structure of acetic acid is considered acidic or ionizable?
D
The hydrogen phosphate ion, HPO42-, can act as both a Bronsted acid and Bronsted base in water. Select all the options that correctly describe the reaction that occurs when HPO42- acts as a Bronsted base in water.
H2PO4- is one of the products. H2O acts as the Bronsted acid. OH- is one of the products.
Which of the following statements correctly describes the relative strength of binary acids?
H2S is a stronger acid than H2O.
Which of the following statements correctly explain the relative strengths of the oxoacids shown: HBrO < HClO < HClO2 < HClO3? Select all that apply.
HClO3 is stronger than HClO2 because HClO3 has more O atoms. HBrO is weaker than HClO because Br is less electronegative than Cl.
Which of the following compounds are strong acids? Select all that apply.
HI HClO4 H2SO4
Which of the following combinations could be used in an acid-base buffer system? Select all that apply.
HNO2 /KNO2 NH3 /NH4Cl CH3COOH/NaCH3COO
Which of the following statements correctly describe the acid-base properties of a 1.0-M solution of methylammonium fluoride (CH3NH3F)? Select all that apply. Ka of HF = 7.1 × 10-4 and Kb of CH3NH2 = 4.4 × 10-4
Ka of CH3NH3+ = 2.3 × 10-11 The solution will be slightly acidic because Ka of CH3NH3+ > Kb of F-. Both CH3NH3+ and F- will hydrolyze (react with water) in aqueous solution.
In order to determine whether a solution of NH4C2H3O2 is acidic, basic, or neutral, what two values could be compared?
Ka of NH4+ Kb of CH3COO-
Which of the following quantities must be known in order to calculate the pH of an acid-base buffer solution using the Henderson-Hasselbalch equation? Select all that apply.
Ka of weak acid or Kb of weak base Concentration of weak acid Concentration of conjugate base
Select all the statements that correctly describe the acid-base behavior of oxides.
Most nonmetal oxides are acidic. Alkali metal oxides are basic. Some metals from Group 13(3A) form amphoteric oxides.
What is the conjugate base of HNO2 if it reacts as a Bronsted acid in H2O?
NO2-
Which of the following salt solutions will be basic, assuming that all have concentrations of 0.1 M? Select all that apply.
NaCN KCH3COO
Select all the compounds in the following list that are strong bases.
NaOH Ca(OH)2
Which of the following options correctly describe the structural characteristics of strong and weak bases? Select all that apply.
Soluble hydroxides are strong bases. Compounds that contain electron-rich N are weak bases. Amines such as CH3CH2NH2 are weak bases.
Consider the ionization of the weak acid HClO2: HClO2 (aq) + H2O (l) ⇌ ClO2- (aq) + H3O+ (aq) Select all the statements that correctly describe the effect of adding KClO2 to this system.
The % ionization of HClO2 will decrease. The solution pH will increase.
Calculate and compare the pH values for 0.10 M solutions of NH4Br (Ka 5.6 × 10-10) and Al(NO3)3 (Ka 1.3 × 10-5). Which of the following statements correctly describe the acidity of these solutions? Select all that apply.
The NH4Br solution has a higher pH than the Al(NO3)3 solution. The pH of the Al(NO3)3 solution is 2.94.
An aqueous NaCl solution was found to have a pH = 7.00. Select all the statements that correctly describe this solution.
The NaCl solution was neutral. Neither Na+ nor Cl- reacts with water.
If the pH of a 0.010 M solution of a strong base is 12.30, what is the identity of the base?
The base could be Ba(OH)2.
Which of the hydrogens in chloroacetic acid is(are) considered acidic or ionizable?
The hydrogen bonded to oxygen
Which of the following factors will affect the relative strength of oxoacids? Select all that apply.
The number of O atoms attached to the central nonmetal atom The electronegativity of the central nonmetal atom
calculate and compare the pH values for 0.10 M solutions of NH4Br (Ka 5.6 × 10-10) and Al(NO3)3 (Ka 1.3 × 10-5). Which of the following statements correctly describe the acidity of these solutions? Select all that app
The pH of the Al(NO3)3 solution is 2.94. The NH4Br solution has a higher pH than the Al(NO3)3 solution.
If NaClO (aq) is added to the reaction shown below, which of the following statements would be true? Select all that apply. HClO (aq) + H2O (l) ⇌ ClO- (aq) + H3O+ (aq)
The pH of the solution would increase. The concentration of HClO (aq) would increase.
Which of the following should be considered when selecting/preparing a buffer solution? Select all that apply.
The ratio of conjugate base to weak acid should be less than 10 and greater than 0.1. The pKa of the weak acid component of the buffer should be close to the desired pH.
As the reaction quotient Q increases, what is the effect on the spontaneity of a given reaction?
The reaction becomes less spontaneous.
Which of the following statements correctly describe the relationship between a weak acid or base and its conjugate base or acid? Select all that apply.
The weaker an acid is, the stronger its conjugate base will be. The stronger a base is, the more strongly the formation of its conjugate acid is favored.
Select all the statements that correctly describe the acid-base behavior of H2O.
Water is amphoteric. In aqueous NH3, water acts as a Bronsted acid. In aqueous HCl, water acts as a Bronsted base.
Which of the following options correctly represent the relationship between [H3O+] and [OH-] in aqueous solutions at 25°C? Select all that apply.
[H3O+] = 1.0×10^−14/[OH−] [H3O+][OH-] = 1.0 × 10-14
Calculate the pH and [H3O+] of a 0.080 M solution of NaOH.
[H3O+] = 1.3 × 10-13 M pH = 12.90
Which of the following gives the correct mathematical operation required to calculate the [H3O+] given a pH of 5.0?
[H3O+] = 10^-5.0
Consider a buffer solution consisting of 0.35 M HNO2 and 0.50 M KNO2, which has an initial pH of 3.30 (Ka for HNO2 = 7.1 × 10-4). If 0.030 mol of HCl are added to 1.0 L of this solution, select all the options that correctly reflect the steps required to calculate the change in pH.
[H3O+] = 7.1 × 10-4 × 0.380/.47 pH = -log(7.1×10−4×0.380/.47)7.1×10-4×0.380.47 = 3.24
Given the balanced chemical equation 2NO2 (g) ⇌ 2NO (g) + O2 (g), what is the expression for K for the reverse reaction?
[NO2]2/[NO]2[O2]
A 0.10 M NH4Cl solution is found to be acidic. Select the statement that correctly represents the relative [H3O+] and [OH-] in this solution.
[OH-] < [H3O+]
Which of the following gives the correct mathematical operation required to calculate the concentration of hydroxide ions in a solution having a pOH of 9.38?
[OH-] = 10^-9.38
Calculate the pH and [OH-] of a solution of a 1.5 M solution of HCl.
[OH-] = 6.7 × 10-15 M pH = -0.18
Which of the following options correctly describe a solution with a pH = 8.00? Select all that apply.
[OH-] > [H3O+] The solution is basic.
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 ___bond to H+.
acceptor; lone; electrons; covalent
A Lewis acid is any species that _____ an electron pair, whereas a Lewis base is a species that _____ an electron pair.
accepts; donates
Like other metal hydroxides, amphoteric hydroxides react with strong acids to produce metal ions and water. However, amphoteric hydroxides also react with _____ to produce complex hydroxides bound to the metal ion.
bases
For a weak acid that has been dissolved in water, the ionization equilibrium will shift toward the reactants if a quantity of the conjugate base is added to the solution. This is an example of the ___ ___effect.
common ion
For a given reaction, Kc is the equilibrium constant based on the of ___reactants and products while Kp is the equilibrium constant based on the partial ____ of reactants and products.
concentration; pressure
In a Bronsted-Lowry acid-base reaction, the acid reacts to form its _____ and the base will form its _____.
conjugate base; conjugate acid
True or false: For any acid-base reaction, Ka x Kb = Kw for the reacting acid and base.
false
If the value of the equilibrium constant K for the forward reaction is less than 1, the value of K for the reverse reaction is _____ 1.
greater then
Arrange the following compounds in order of increasing acid strength (weakest at the top to strongest at the bottom of the list).
h20, hf, hbr
The strength of an acid is measured by its tendency to___ and produce___ ions in aqueous solution.
ionize; hydrogen
Consider the equilibrium system NH3 (aq) + H2O (l) ⇌ NH4+ (aq) + OH- (aq). If some solid NH4Cl were added to the system, the equilibrium would shift to the _____ and the [OH-] would _____.
left; decrease
When [H3O+] = [OH-], the solution is
neutral
Consider a buffer solution consisting of 1.0 M HF and 1.0 M NaF, which has an initial pH of 3.14 (Ka for HF = 7.2 × 10-4). Use the Henderson-Hasselbalch equation to determine the new pH after 0.10 mol of NaOH is added to 1.0 L of this solution.
pH = 3.23
A buffer solution consists of 0.45 M HCOOH and 0.63 M HCOONa (pKa for HCOOH = 3.74). Which option shows the correct calculation for the pH of the buffer after 0.020 mol of solid NaOH is added to 1.0 L of the solution?
pH = 3.74 + log0.650/.43
Consider a buffer made by combining equal volumes of 0.15 M CH3COOH and 0.32 M NaC2H3O2. What is the pH of this buffer if the Ka for CH3COOH is 1.8 × 10-5?
pH = 5.07
Which of the following mathematical relationships are correct for an aqueous solution at 25°C? Select all that apply.
pOH + pH = 14.00 pH = -log[H3O+]
Hydrated _____ metal cations act as weak acids because these metal ions are so successful at withdrawing electron density from the O-H bond of water, thus facilitating the loss of H+ to the solvent water to form H3O+.
small, highly charged
For a buffer system composed of a weak acid-conjugate base, [H+] = Ka [HA]/A-]. As long as the amounts of HA and A- are large relative compared to the amounts of OH- or H+ added, the change in [HA]/[A-] will be___ and the change in [H+], and thus pH, will be ___ .
small, small
For a buffer system composed of a weak acid-conjugate base, [H+] = Ka [HA]/[A-]. As long as the amounts of HA and A- are large relative compared to the amounts of OH- or H+ added, the change in [HA]/[A-] will be and the change in [H+], and thus pH, will be
small; small
When a strong acid or base is added to a buffer system, there is a ______ change in the [HA]/[A-] ratio and thus a ______ change in pH.
small; small
The two factors that influence the extent of ionization of an acid are the___ and ___of the HX bond, where HX is the general formula of an acid.
strength; polarity
1.9 moles of HI are added to an evacuated, sealed 10.-L container and allowed to decompose according to the chemical equation: H2 (g) + I2 (g) ⇌ 2HI (g); Kc = 1.26 × 10−3H2 (g) + I2 (g) ⇌ 2HI (g); Kc = 1.26 × 10-3 Select all the statements that correctly describe this system.
-If the change in [H2] = +xH2 = +x, then at equilibrium [I2] = xI2 = x. -Kc = 1.26 ×10−3 = (0.19 −2x)^2/x^2 -The initial [HI] = 0.19 MHI = 0.19 M. because [HI]HI at the start = 1.9 mol/10L
The magnitude of the equilibrium constant and the sign of the standard Gibbs Energy change provide useful information about a reaction. Match the correct correlation between the two. Instructions
-K>>1= ΔGo < 0 and the reaction is spontaneous as written -K<<1= ΔGo > 0 and the reaction is spontaneous as written
0.45 mol PCl5 (g) is placed in a sealed 2.0-L container and reacts according to the equation: PCl5 (g) ⇌ PCl3 (g) + Cl2 (g). If [Cl2] = 0.10 M at equilibrium, select all the options that correctly reflect the steps required to calculate Kc.
-Kc = (0.10)(0.10)/(0.13) -At equilibrium [PCl3] = 0.10 M. because 1 mol PCl3 forms for every 1 mol Cl2 that forms. -The initial [PCl5] = 0.23 M.
Based on the equation ΔG = ΔG° + RT ln(Q), match each range of Q values to the effect it has on the spontaneity of the reaction. Instructions
-Q < 1-The forward reaction will be more favored and the reverse reaction less favored than at standard conditions. -Q = 1 There will be no change in spontaneity from standard conditions. -Q > 1The reverse reaction will be more favored and the forward reaction less favored than at standard conditions.
Which of the following statements accurately describe Bronsted-Lowry acid-base reactions? Select all that apply.
-Some species can act as either an acid or a base depending on the other species present. -The reactants and products contain an acid and a base.
How does a conjugate acid differ from its conjugate base? Select all that apply.
-The conjugate acid has one more H than its conjugate base. -The conjugate acid of a neutral base will have a charge of +1. -A conjugate base may be positively charged, neutral, or negatively charged.
Explain the importance of the equation ΔGo = -RT ln K.
-The magnitude and sign of ΔGo correlate to how large or small is the value of K. -ΔGo can be calculated from tabulated thermodynamic data.
Consider a buffer solution consisting of 1.0 M HF and 1.0 M NaF, which has an initial pH of 3.14 (Ka for HF = 7.2 × 10-4). If 0.10 mol of NaOH is added to 1.0 L of this solution, select all the options that correctly reflect the steps required to calculate the change in pH. Assume no volume changes.
-pHafter addition = -log(7.2×10−4×0.90/1.10) -pHafter addition = -log (5.89 × 10-4) = 3.23 -After OH- has been consumed, [HF] = 0.90 M, [F-] = 1.10 M. -[H+]after addition = 7.2 × 10-4 × 0.90/1.10
Select all the statements that correctly describe the equation below. KP = Kc(RT)Δn
-Δn indicates the change in the number of moles of gases in the reaction. -The gas constant is usually expressed as R = 0.08206 L⋅atm/mol⋅K
Match each equation to the correct value for ∆n∆n. Instructions
-∆n = 0-> H2 (g) + I2 (g) ⇌ 2HI (g) -∆n = −1 -> 3O2 (g) ⇌ 2O3 (g) -∆n = 1 -> CO2 (s) ⇌ CO2 (g)
Calculate the Ka value for the anilium ion (C6H5NH3+) if Kb for aniline (C6H5NH2) is 4.0 x 10-10.
2.5 × 10-5
Select the correct relationship between the original Kc value and the new Kc' value when the original chemical equation is multiplied by a coefficient, n.
Kc' = (Kc)n
Select all the reactions in which the Lewis acid is a cation and the Lewis base is a molecule with one or more lone pairs of electrons.
Fe3+ + 6H2O ⇌ Fe(H2O)63+ Ni2+ + 6NH3 ⇌ Ni(NH3)62+
Which of the following statements describes the common ion effect?
For a solution of a weak acid in water, addition of the conjugate base will shift the ionization equilibrium.
Which of the following statements correctly explains why even distilled and deionized H2O contains some ions?
H+ can be transferred from one H2O molecule to another, forming H3O+ and -OH ions.
Which statement best explains the trend in acid strength: H2SO4 > H2SO3 > H2SeO3?
H2SO4 is stronger than H2SO3 because it has more O atoms.
Which of the following formulas can be used to represent a hydrogen ion in aqueous solution?
H3O+ H+
Water is an amphoteric species. Match the product formed from water acting as an acid or a base. Instructions
H3O+-> Water acting as a base. Water acting as a base. OH--> Water acting as an acid. Water acting as an acid.
Which of the following acids are polyprotic?
H3PO4 H2SO3
Match each acid correctly to the number of ionizable protons.
H3PO4-> 3 H2CO3->2 CH3COOH->1
Select the correct relationship between the original Kc values for a two-step process and the new Kc' value for the overall reaction (the sum of the steps).
Kc' = (Kc1 x Kc2)
Which of the following conjugate acid-base pairs is the best choice to prepare a buffer of pH 3.50?
HCOOH/HCOONa (pKa of HCOOH = 3.74)
Which of the following statements correctly describe the relative strengths of acids and bases, and of conjugate acid-base pairs? Select all that apply.
Iodide ion, the conjugate base of HI, is a weak base. CH3COO- is a relatively stronger base than Cl3CCOO-.
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− NO−3
How does the equilibrium constant K change when all the coefficients of a balanced equation are multiplied by the same factor, n?
K' = Kn where n is the factor by which the coefficients are multiplied.
Determine if aqueous solutions of the following salts are acidic, basic, or neutral. Instructions
KBr->neutral NH4INH4I->acidic KCN-> basic
Select the correct expression for the relationship between Kc and KP.
KP = Kc(RT)Δn
Match the correct qualitative prediction for a salt solution in which both its cation and anion hydrolyze. Instructions
Ka (of the salt's cation) > Kb (of the salt's anion)=The salt solution is acidic. Ka (of the salt's cation) < Kb (of the salt's anion)=The salt solution is basic. Ka (of the salt's cation) ≈ Kb (of the salt's anion)= The salt solution is neutral.
Select all the expressions that correctly express the relationship between Ka and Kb for a conjugate acid-base pair.
Ka = Kw/Kb Ka × Kb = Kw
Which of the following types of substances are classified as acids only under the Lewis definition? Select all that apply.
Molecules with electron deficient central atoms Molecules that contain a polar multiple bond
Which of the following nonmetal oxides produce a weak acid when dissolved in water? Select all that apply.
P4O10 CO2
Consider a general buffer system made from a weak acid, HA, and its conjugate base A-. Select all the statements that describe the behavior of this system when strong acid is added to it.
The overall pH will decrease only slightly. The ratio [HA]/[A-] will increase. The [A-] in solution will decrease.
Select all the options that correctly account for the behavior of NH4Cl in aqueous solution.
The solution will have a pH < 7.00. NH4+ + H2O ⇌ NH3 + H3O+
An amphoteric substance can behave as either a(n) ___or a(n)___ .
acid; base
One type of acid-base buffer is composed of a weak___ , which will react with any added base, and its conjugate___ , which will react with any added acid.
acid; base
A salt in which the cation is the conjugate acid of a weak base will be ______. (Assume that the anion does not hydrolyze.)
acidic
In general, nonmetal oxides tend to be _____ while metal oxides tend to be _____.
acidic, basic
In an aqueous solution at a given temperature, the product [H3O+][OH-] has a _____ value. This product is equal to _____ at 25oC.
constant, 1.0 x 10^-14
The product of a Lewis acid-base reaction contains a new bond called a covalent bond.
coordinate
When Q > K, the amount of products must _____ and the amount of reactants must _____ for equilibrium to be established. Thus, when Q > K, the reaction will proceed toward the _____ to establish equilibrium.
decrease, increase, reactants
As a reaction proceeds in the reverse direction to establish equilibrium, the value of Q _____.
decreases
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
An acid can be defined as a substance that loses one or more H+ ions when dissolved in water. An H+ ion is a hydrogen atom that has lost a(n) and is therefore just a(n) . The H+ ion is not an isolated ion, but interacts strongly with H2O to produce the ion, which has the formula H3O+.
electron; proton; hydronium
An acid can be defined as a substance that loses one or more H+ ions when dissolved in water. An H+ ion is a hydrogen atom that has lost a(n)___ and is therefore just a(n) ___ . The H+ ion is not an isolated ion, but interacts strongly with H2O to produce the ___ ion, which has the formula H3O+.
electron; proton; hydronium
The two types of strong acids are binary acids containing hydrogen bonded to a(n) _____ atom and oxoacids in which the number of O atoms exceeds the number of ionizable protons by _____ or more.
halogen; 2
The autoionization of water is a process where water ionizes very slightly to form___ ions and ___ions. (Remember to include charges for the ions but no symbols to indicate super- or sub-scripts.)
hydronium; hydroxide
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
Which of the following is the correct expression for the Henderson-Hasselbalch equation, which is used to calculate the pH of an acid-base buffer solution?
pH = pKa + log([base]/[acid])
Three common ways of applying a stress to a system at equilibrium are to change (1) the concentration of reactants and/or products, (2) the temperature, or (3) the___ of a system involving gaseous reactants and products.
pressure
An acid-base reaction occurs when one species loses a(n) ___and another species simultaneously ___ a proton. An acid-base reaction can therefore be viewed as a proton-___ process.
proton; gains; transfer
According to the Le Chatelier's principle, the addition of an ion in common with a weak acid will _____, thus changing the pH from that of the pure acid.
shift the equilibrium to the left
The value of Kp for a given reaction is the equilibrium constant based on _____.
the partial pressures of the reactants and products
The value of the equilibrium constant K for the forward reaction is _____ the value of K for the reverse reaction.
the reciprocal of
In the reaction illustrated here, a proton is transferred from _____, which is the Bronsted _____, to _____, which acts as the Bronsted _____.
water, acid, ammonia, base
In general, the stronger an acid is, the _____ its conjugate base will be. The stronger the acid, the more the equilibrium shown below will favor the formation of the _____. HA + H2O ⇌ H3O+ + A-
weaker, conjugate base
The value of Q equals _____ when an initial experimental mixture contains only reactants. In order to move towards equilibrium reactant concentrations decrease and product concentrations increase.
zero
Under equilibrium conditions, the equation ΔG = ΔGo + RT ln Q simplifies to which of the following?
ΔGo = -RT ln K