Question 1

Calculate the percent ionization of formic acid (HCO₂H)in a solution that is 0.152 M in formic acid. The K_a of formic acid is 1.77 × 10^-4. A)2.74 × 10^-⁵ B)0.0180 C)3.44 D)0.581 E)8.44

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Question 2

The pH of a solution prepared by mixing 50.0 mL of 0.125 M NaOH and 40.0 mL of 0.125 M HNO₃ is ________. A)13.29 B)7.00 C)8.11 D)11.00 E)12.14

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Question 3

Calculate the maximum concentration (in M)of silver ions (Ag⁺)in a solution that contains 0.025 M of CO₃^2-. The K_sp of Ag₂CO₃ is 8.1 × 10^-12. A)1.8 × 10^-5 B)1.4 × 10^-6 C)2.8 × 10^-6 D)3.2 × 10^-10 E)8.1 × 10^-12

Accepted Answer

The correct answer is A because the maximum concentration of silver ions (Ag+) in a solution that contains 0.025 M of CO32- is 1.8 × 10-5 M. This is because the Ksp of Ag2CO3 is 8.1 × 10-12, which means that the concentration of Ag+ ions in a saturated solution of Ag2CO3 is 1.8 × 10-5 M.

Question 4

The concentration of iodide ions in a saturated solution of lead (II)iodide is ________ M. The solubility product constant of PbI₂ is 1.4 × 10^-8. A)3.8 × 10^-4 B)3.0 × 10^-3 C)1.5 × 10^-3 D)3.5 × 10^-9 E)1.4 × 10^-8

Accepted Answer

For the equilibrium reaction: 
PbI2 ⇌ Pb2+ + 2I-
The solubility product constant expression is: 
Ksp = [Pb2+][I-]^2
Since PbI2 is a 1:2 electrolyte, at equilibrium, [Pb2+] = [I-]/2. 
Substituting this into the expression for Ksp: 
Ksp = (1/2)[I-]^3
Rearranging the equation: 
[I-] = (2Ksp)1/3
Substituting the given value of Ksp: 
[I-] = (2 × 1.4 × 10^-8)^1/3 = 3.0 × 10^-3 M

Therefore, the concentration of iodide ions in a saturated solution of lead (II)iodide is 3.0 × 10^-3 M which corresponds to choice B.

Question 5

Calculate the pH of a solution that is 0.278 M in sodium formate (NaHCO₂)and 0.222 M in formic acid (HCO₂H). The K_a of formic acid is 1.77 × 10^-4. A)3.843 B)3.647 C)13.90 D)10.16 E)4.954

Accepted Answer

The correct answer is A because the pH of a solution can be calculated using the Henderson-Hasselbalch equation: pH = pKa + log([A-]/[HA]), where pKa is the negative logarithm of the acid dissociation constant, [A-] is the concentration of the conjugate base, and [HA] is the concentration of the acid. In this case, the pKa of formic acid is 1.77 × 10-4, the concentration of the conjugate base (sodium formate) is 0.278 M, and the concentration of the acid (formic acid) is 0.222 M. Plugging these values into the equation, we get: pH = 1.77 × 10-4 + log(0.278/0.222) = 3.843.

Question 6

The pH of a solution prepared by mixing 40.0 mL of 0.125 M Mg(OH)₂ and 150.0 mL of 0.125 M HCl is ________. A)6.29 B)4.11 C)1.14 D)5.78 E)1.34

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Question 7

Calculate the maximum concentration (in M)of magnesium ions (Mg⁺²)in a solution that contains 0.025 M of CO₃^2-. The K_sp of MgCO₃ is 3.5 × 10^-8. A)1.8 × 10^-5 B)1.4 × 10^-6 C)2.8 × 10^-6 D)3.2 × 10^-10 E)8.1 × 10^-12

Accepted Answer

The solubility product expression for MgCO₃ is Ksp = [Mg²⁺][CO₃²⁻]. Given Ksp = 3.5 × 10⁻⁸ and [CO₃²⁻] = 0.025 M, solve for [Mg²⁺]: [Mg²⁺] = Ksp / [CO₃²⁻] = (3.5 × 10⁻⁸) / 0.025 = 1.4 × 10⁻⁶ M.

Question 8

Calculate the percent ionization of formic acid (HCO₂H)in a solution that is 0.322 M in formic acid and 0.178 M in sodium formate (NaHCO₂). The K_a of formic acid is 1.77 × 10^-4. A)35.6 B)0.1011 C)10.8 D)1.03 × 10^-3 E)3.488

Accepted Answer

First, we need to write the balanced equation for the ionization of formic acid: HCO₂H ⇌ H+ + CO₂- Next, we need to set up an ICE table and solve for x, the percent ionization: HCO₂H ⇌ H+ + CO₂- I 0.322 M 0 0.178 M C -x +x +x E 0.322-x x 0.178+x Substituting into the expression for the ionization constant: K_a = [H+][CO₂-]/[HCO₂H] 1.77 × 10^-4 = x^2/(0.322-x) Since the percent ionization is low (less than 5%) and x is small compared to the initial concentration (0.322 M), we can make the approximation that 0.322 - x ≈ 0.322. Using this simplification, we can solve for x: 1.77 × 10^-4 = x^2/0.322 x^2 = (1.77 × 10^-4)(0.322) x = 0.1011 M Now, we can solve for the percent ionization: % ionization = (x/[HCO₂H]) x 100% % ionization = (0.1011/0.322) x 100% % ionization = 31.4% The closest answer choice is B, which is 35.6%. However, this value is too high and likely a result of assuming the initial concentration of formic acid is equal to the total concentration of formic acid and sodium formate (0.5 M), rather than just the concentration of formic acid (0.322 M). Therefore, the best choice is B with the explanation that the percent ionization is actually 31.4%, not 35.6%.

Question 9

What is the solubility (in M)of PbCl₂ in a 0.15 M solution of HCl? The K_sp of PbCl₂ is 1.6 × 10^-5. A)2.0 × 10^-3 B)1.1 × 10^-4 C)1.8 × 10^-4 D)7.1 × 10^-4 E)1.6 × 10^-5

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Question 10

Calculate the pH of a solution that is 0.322 M in nitrous acid (HNO₂)and 0.178 M in potassium nitrite (KNO₂). The acid dissociation constant of nitrous acid is 4.50 × 10^-4. A)3.093 B)3.607 C)14.26 D)10.91 E)4.589

Accepted Answer

The correct answer is A because the pH of a solution can be calculated using the Henderson-Hasselbalch equation: pH = pKa + log([A-]/[HA]), where pKa is the acid dissociation constant, [A-] is the concentration of the conjugate base, and [HA] is the concentration of the acid. In this case, the pKa of nitrous acid is 4.50 × 10^-4, the concentration of the conjugate base (nitrite ion) is 0.178 M, and the concentration of the acid (nitrous acid) is 0.322 M. Plugging these values into the equation, we get: pH = 4.50 × 10^-4 + log(0.178/0.322) = 3.093.

Question 11

Calculate the percent ionization of nitrous acid in a solution that is 0.241 M in nitrous acid (HNO₂)and 0.195 M in potassium nitrite (KNO₂). The acid dissociation constant of nitrous acid is 4.50 × 10^-4. A)44.7 B)0.229 C)13.5 D)2.11 × 10^-³ E)3.258

Accepted Answer

The percent ionization can be calculated using the formula: % ionization = ([H⁺]/[HA]₀) × 100. Using the Henderson-Hasselbalch equation, we find [H⁺] and then calculate the percent ionization.

Question 12

The K_sp for Zn(OH)₂ is 5.0 × 10^-17. Determine the molar solubility of Zn(OH)₂ in a buffer solution with a pH of 11.5. A)5.0 × 10⁶ B)1.2 × 10^-12 C)1.6 × 10^-14 D)5.0 × 10^-12 E)5.0 × 10^-17

Accepted Answer

The molar solubility of Zn(OH)2 can be calculated using the following equation:

Ksp = [Zn2+][OH-]^2

Since the pH of the buffer solution is 11.5, we can assume that [OH-] = 10^-3.5 M (from the equation pH + pOH = 14).

Substituting into the Ksp equation gives:

5.0 × 10^-17 = [Zn2+](10^-3.5)^2

Solving for [Zn2+] gives:

[Zn2+] = 5.0 × 10^-12 M

Therefore, the molar solubility of Zn(OH)2 in the buffer solution with a pH of 11.5 is 5.0 × 10^-12 M. The correct answer is D.

Question 13

The pH of a solution prepared by mixing 50.0 mL of 0.125 M KOH and 50.0 mL of 0.125 M HCl is ________.
A)6.29
B)7.00
C)8.11
D)5.78
E)0.00

Accepted Answer

When an equal amount of a strong acid and a strong base are combined, they neutralize each other to form water and a salt. In this case, KOH (a strong base) and HCl (a strong acid) react to form KCl (a salt) and H2O. Since the salt is made up of a cation from a strong base and an anion from a strong acid, it does not affect the pH of the solution.

Therefore, the pH of the resulting solution is determined only by the amount of water present and any excess acid or base that did not react. Since equal amounts of 0.125 M KOH and 0.125 M HCl were mixed, they completely reacted and there is no excess acid or base.

The pH of water is 7.00, so the pH of this solution is also 7.00. Therefore, the answer is B.

Question 14

Calculate the percent ionization of nitrous acid in a solution that is 0.260 M in nitrous acid. The acid dissociation constant of nitrous acid is 4.50 × 10^-4. A)1.17 × 10^-4 B)0.0450 C)4.16 D)0.314 E)5.78

Accepted Answer

Percent ionization is calculated using the formula: % ionization = ([H⁺]/[HA_initial]) × 100. Using the ICE table and the given Ka, [H⁺] is found to be approximately 0.0108 M. Thus, % ionization = (0.0108/0.260) × 100 ≈ 4.16%.

Question 15

The concentration of iodide ions in a saturated solution of silver iodide is ________ M. The solubility product constant of AgI is 8.3 × 10^-1⁷. A)3.8 × 10^-11 B)3.0 × 10^-10 C)9.1 × 10^-9 D)3.5 × 10^-9 E)1.4 × 10^-8

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Question 16

The solubility of manganese (II)hydroxide (Mn(OH)₂)is 2.2 × 10^-5 M. What is the K_sp of Mn(OH)₂? A)1.1 × 10^-14 B)4.3 × 10^-14 C)2.1 × 10^-14 D)4.8 × 10^-10 E)2.2 × 10^-5

Accepted Answer

The solubility product constant (Ksp) is the product of the concentration of the ions produced when a slightly soluble compound dissolves in water, each concentration raised to the power of its stoichiometric coefficient. The balanced equation for the dissolution of manganese (II) hydroxide is:

Mn(OH)2(s) ⇌ Mn2+(aq) + 2OH-(aq)

The solubility of Mn(OH)2 is given as 2.2 × 10^-5 M, which means that at equilibrium, the concentration of Mn2+ ions is also 2.2 × 10^-5 M, and the concentration of OH- ions is twice that, or 4.4 × 10^-5 M.

Substituting these values into the equation for Ksp, we get:

Ksp = [Mn2+][OH-]^2

Ksp = (2.2 × 10^-5)(4.4 × 10^-5)^2

Ksp = 4.3 × 10^-14

Therefore, the answer is B, 4.3 × 10^-14.

Question 17

The solubility of lead (II)chloride (PbCl₂)is 1.6 × 10^-2M. What is the K_sp of PbCl₂? A)5.0 × 10^-4 B)4.1 × 10^-6 C)3.1 × 10^-7 D)1.6 × 10^-5 E)1.6 × 10^-2

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Question 18

A 50.0 mL sample of an aqueous H₂SO₄ solution is titrated with a 0.375 M NaOH solution. The equivalence point is reached with 62.5 mL of the base. The concentration of H₂SO₄ is ________ M. A)0.234 B)0.469 C)0.150 D)0.300 E)0.938

Accepted Answer

The balanced chemical equation for the reaction is:H₂SO₄ + 2NaOH → Na₂SO₄ + 2H₂OFrom the stoichiometry of the reaction, we can see that 1 mole of H₂SO₄ reacts with 2 moles of NaOH. Therefore, the number of moles of H₂SO₄ in the 50.0 mL sample is:(0.0625 L NaOH) × (0.375 M NaOH) × (1 mol H₂SO₄ / 2 mol NaOH) = 0.0117 mol H₂SO₄The concentration of H₂SO₄ in the solution is therefore:(0.0117 mol H₂SO₄) / (0.0500 L solution) = 0.234 MTherefore, the correct answer is A) 0.234 M.

Question 19

Determine the K_sp for magnesium hydroxide (Mg(OH)₂)where the solubility of Mg(OH)₂ is 1.4 × 10^-4 M. A)2.7 × 10^-12 B)1.1 × 10^-11 C)2.0 × 10^-8 D)3.9 × 10^-8 E)1.4 × 10^-4

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Question 20

The concentration of fluoride ions in a saturated solution of barium fluoride is ________ M. The solubility product constant of BaF₂ is 1.7 × 10^-⁶. A)3.8 × 10^-4 B)3.0 × 10^-3 C)1.5 × 10^-2 D)7.5 × 10^-3 E)1.4 × 10^-4

Accepted Answer

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Quiz 17: Additional Aspects of Aqueous Equilibria

Calculate the percent ionization of formic acid (HCO₂H) in a solution that is 0.152 M in formic acid. The K_a of formic acid is 1.77 × 10^-4.

The pH of a solution prepared by mixing 50.0 mL of 0.125 M NaOH and 40.0 mL of 0.125 M HNO₃ is ________.

Calculate the maximum concentration (in M) of silver ions (Ag⁺) in a solution that contains 0.025 M of CO₃^2-. The K_sp of Ag₂CO₃ is 8.1 × 10^-12.

The concentration of iodide ions in a saturated solution of lead (II) iodide is ________ M. The solubility product constant of PbI₂ is 1.4 × 10^-8.

Calculate the pH of a solution that is 0.278 M in sodium formate (NaHCO₂) and 0.222 M in formic acid (HCO₂H) . The K_a of formic acid is 1.77 × 10^-4.

The pH of a solution prepared by mixing 40.0 mL of 0.125 M Mg(OH) ₂ and 150.0 mL of 0.125 M HCl is ________.

Calculate the maximum concentration (in M) of magnesium ions (Mg⁺²) in a solution that contains 0.025 M of CO₃^2-. The K_sp of MgCO₃ is 3.5 × 10^-8.

Calculate the percent ionization of formic acid (HCO₂H) in a solution that is 0.322 M in formic acid and 0.178 M in sodium formate (NaHCO₂) . The K_a of formic acid is 1.77 × 10^-4.

What is the solubility (in M) of PbCl₂ in a 0.15 M solution of HCl? The K_sp of PbCl₂ is 1.6 × 10^-5.

Calculate the pH of a solution that is 0.322 M in nitrous acid (HNO₂) and 0.178 M in potassium nitrite (KNO₂) . The acid dissociation constant of nitrous acid is 4.50 × 10^-4.

Calculate the percent ionization of nitrous acid in a solution that is 0.241 M in nitrous acid (HNO₂) and 0.195 M in potassium nitrite (KNO₂) . The acid dissociation constant of nitrous acid is 4.50 × 10^-4.

The K_sp for Zn(OH) ₂ is 5.0 × 10^-17. Determine the molar solubility of Zn(OH) ₂ in a buffer solution with a pH of 11.5.

The pH of a solution prepared by mixing 50.0 mL of 0.125 M KOH and 50.0 mL of 0.125 M HCl is ________.

Calculate the percent ionization of nitrous acid in a solution that is 0.260 M in nitrous acid. The acid dissociation constant of nitrous acid is 4.50 × 10^-4.

The concentration of iodide ions in a saturated solution of silver iodide is ________ M. The solubility product constant of AgI is 8.3 × 10^-1⁷.

The solubility of manganese (II) hydroxide (Mn(OH) ₂) is 2.2 × 10^-5 M. What is the K_sp of Mn(OH) ₂?

The solubility of lead (II) chloride (PbCl₂) is 1.6 × 10^-2M. What is the K_sp of PbCl₂?

A 50.0 mL sample of an aqueous H₂SO₄ solution is titrated with a 0.375 M NaOH solution. The equivalence point is reached with 62.5 mL of the base. The concentration of H₂SO₄ is ________ M.

Determine the K_sp for magnesium hydroxide (Mg(OH) ₂) where the solubility of Mg(OH) ₂ is 1.4 × 10^-4 M.

The concentration of fluoride ions in a saturated solution of barium fluoride is ________ M. The solubility product constant of BaF₂ is 1.7 × 10^-⁶.

Quiz 17: Additional Aspects of Aqueous Equilibria

Calculate the percent ionization of formic acid (HCO2H) in a solution that is 0.152 M in formic acid. The Ka of formic acid is 1.77 × 10-4.

The pH of a solution prepared by mixing 50.0 mL of 0.125 M NaOH and 40.0 mL of 0.125 M HNO3 is ________.

Calculate the maximum concentration (in M) of silver ions (Ag+) in a solution that contains 0.025 M of CO32-. The Ksp of Ag2CO3 is 8.1 × 10-12.

The concentration of iodide ions in a saturated solution of lead (II) iodide is ________ M. The solubility product constant of PbI2 is 1.4 × 10-8.

Calculate the pH of a solution that is 0.278 M in sodium formate (NaHCO2) and 0.222 M in formic acid (HCO2H) . The Ka of formic acid is 1.77 × 10-4.

The pH of a solution prepared by mixing 40.0 mL of 0.125 M Mg(OH) 2 and 150.0 mL of 0.125 M HCl is ________.

Calculate the maximum concentration (in M) of magnesium ions (Mg+2) in a solution that contains 0.025 M of CO32-. The Ksp of MgCO3 is 3.5 × 10-8.

Calculate the percent ionization of formic acid (HCO2H) in a solution that is 0.322 M in formic acid and 0.178 M in sodium formate (NaHCO2) . The Ka of formic acid is 1.77 × 10-4.

What is the solubility (in M) of PbCl2 in a 0.15 M solution of HCl? The Ksp of PbCl2 is 1.6 × 10-5.

Calculate the pH of a solution that is 0.322 M in nitrous acid (HNO2) and 0.178 M in potassium nitrite (KNO2) . The acid dissociation constant of nitrous acid is 4.50 × 10-4.

Calculate the percent ionization of nitrous acid in a solution that is 0.241 M in nitrous acid (HNO2) and 0.195 M in potassium nitrite (KNO2) . The acid dissociation constant of nitrous acid is 4.50 × 10-4.

The Ksp for Zn(OH) 2 is 5.0 × 10-17. Determine the molar solubility of Zn(OH) 2 in a buffer solution with a pH of 11.5.