Question 1

A 25.00-mL sample of propionic acid, HC₃H₅O₂, of unknown concentration was titrated with 0.145 M KOH. The equivalence point was reached when 43.02 mL of base had been added. What was the original concentration of the propionic acid?

Accepted Answer

The answer of A 25.00-mL sample of propionic acid, HC₃H₅O₂,...

Question 2

The K_sp of Ca(OH)₂ is 5.5 × 10^-5 at 25 °C. What is the concentration of OH^-(aq) in a saturated solution of Ca(OH)₂(aq)?

Accepted Answer

The answer of The K_sp of Ca(OH)₂ is 5.5 ×...

Question 3

The concentration of calcium carbonate in a saturated aqueous solution at 25°C is $6.71 \times 10 ^ { - 5 }$ M. What is the K_sp of this sparingly soluble salt?

Accepted Answer

The solubility product $K_{sp}$ for calcium carbonate, $CaCO_3$, is calculated using the formula $K_{sp} = [Ca^{2+}][CO_3^{2-}]$. Since the concentration of $CaCO_3$ is $6.71 \times 10^{-5}$ M, both $Ca^{2+}$ and $CO_3^{2-}$ ions will have the same concentration in a saturated solution. Therefore, $K_{sp} = (6.71 \times 10^{-5})^2 = 4.5 \times 10^{-9}$.

Question 4

Which of the following indicators is most suitable for the titration of a 25.00-mL sample of 0.140 M propionic acid, HC₃H₅O₂, with strong base?

Accepted Answer

The answer of Which of the following indicators is most...

Question 5

The solubility of manganese(II) carbonate is 5.4 × 10^-4 g/L. What is the solubility product constant for manganese(II) carbonate?

Accepted Answer

The solubility product constant (Ksp) for manganese(II) carbonate, MnCO3, can be calculated from its solubility. MnCO3 dissociates into Mn^2+ and CO3^2- ions in solution. Given the solubility is 5.4 × 10^-4 g/L, we first convert this to moles per liter (molarity, M) using the molar mass of MnCO3 (approximately 114.95 g/mol). This gives a solubility of about 4.7 × 10^-6 M. Since the dissociation produces one mole of Mn^2+ and one mole of CO3^2- for each mole of MnCO3 that dissolves, the concentrations of Mn^2+ and CO3^2- are each 4.7 × 10^-6 M in a saturated solution. The Ksp is the product of these concentrations: (4.7 × 10^-6)^2 = 2.2 × 10^-11.

Question 6

Which is the best colored indicator to use in the titration of 0.1 M CH₃CO₂H(aq) with NaOH(aq)? Why? (K_a of CH₃CO₂H = 1.8 × 10^-5, K_b of CH₃CO₂^- = 5.6 × 10^-10)$$\begin{array} { l l } \text { Indicator } & \mathrm { p } K _ { \mathrm { a } } \ \hline \text { Bromcresol Green } & 4.8 \ \text { Bromthymol Blue } & 6.8 \ \text { Phenolphthalein } & 9.2 \end{array}$$

Accepted Answer

The equivalence point for the titration of a weak acid (CH3CO2H) with a strong base (NaOH) is above pH 7. Phenolphthalein, with a pKa of 9.2, is suitable as it changes color in the basic pH range near the equivalence point.

Question 7

Titration of 0.1615 g of an unknown monoprotic acid dissolved in 25.00 mL of water requires 21.84 mL of 0.1231 M NaOH to reach the endpoint. What is the molar mass of the acid?

Accepted Answer

The answer of Titration of 0.1615 g of an unknown...

Question 8

What is the solubility product expression for La(OH)₃?

Accepted Answer

The solubility product expression for La(OH)₃ is derived from its dissociation: La(OH)₃ ⇌ La³⁺ + 3OH⁻. The expression is Ksp = [La³⁺][OH⁻]³.

Question 9

An impure sample of sodium carbonate, Na₂CO₃, is titrated with 0.113 M HCl according to the reaction below. 2 HCl(aq) + Na₂CO₃(aq) $\leftrightharpoons$ CO₂(g) + H₂O( $\ell$ ) + 2 NaCl(aq) What is the percent of Na₂CO₃ in a 0.613 g sample if the titration requires 26.14 mL of HCl? The molar mass of Na₂CO₃ is 106.0 g/mol.

Accepted Answer

The answer of An impure sample of sodium carbonate, Na₂CO₃,...

Question 10

What is the molar solubility of silver(I) iodide at 25°C? The solubility product constant for silver(I) iodide is 8.3 × 10^-17 at 25°C.

Accepted Answer

The molar solubility of a salt is equal to the square root of its solubility product constant divided by the ion product. At equilibrium, the ion product is equal to the concentration of silver ions multiplied by the concentration of iodide ions, so we have:

AgI(s) ⇌ Ag+(aq) + I-(aq)

Let x be the molar solubility of AgI.
Then, [Ag+] = [I-] = x
The ion product is then: (x)(x) = x^2
Substituting into the solubility product expression gives:

Ksp = [Ag+][I-] = x^2

Rearranging and taking the square root:

x = sqrt(Ksp) = sqrt(8.3e-17) = 9.1e-9 M

Therefore, the answer is A) 9.1 × 10^-9 M.

Question 11

What is the pH of a saturated solution of Fe(OH)₂? (K_sp = 8.0 × 10^-16 and K_w = 1.01 × 10^-14)

Accepted Answer

The answer of What is the pH of a saturated...

Question 12

The K_sp of BaSO₄ is 1.1 × 10^-10 at 25 °C. What mass of BaSO₄ will dissolve in 1.0 L of water at 25 °C? (molar mass = 233.4 g/mol)

Accepted Answer

The answer of The K_sp of BaSO₄ is 1.1 ×...

Question 13

The solubility of strontium carbonate (SrCO₃) in water at 25°C is $4.5 \times 10 ^ { - 3 }$ g/L. What is the K_sp of this sparingly soluble salt?

Accepted Answer

The solubility product (Ksp) is calculated using the molar solubility. Convert the solubility from g/L to mol/L using the molar mass of SrCO3 (147.63 g/mol), then use the formula Ksp = [Sr^2+][CO3^2-] = s^2, where s is the molar solubility.

Question 14

A solution containing 10. mmol of CO₃²⁻ and 5.0 mmol of HCO₃−is titrated with 1.1 M HCl. What total volume of HCl must be added to reach the second equivalence point? (1 mmol = 0.001 mol)

Accepted Answer

The titration equation for CO₃²⁻ and HCO₃− is: CO₃²⁻ + HCl → CO₃− + H2O + Cl− In the first equivalence point, all of the HCO₃− will be neutralized to CO₃−, so the number of moles of HCl required is: mol of HCO₃− = 5.0 mmol mol of HCl = 5.0 mmol Since the concentration of the HCl is 1.1 M, the volume of HCl required is: V = mol of HCl / [HCl] = 5.0 mmol / 1.1 mol/L = 4.5 mL At the second equivalence point, all of the CO₃²⁻ will be neutralized to CO₃−, so the total number of moles of HCl required is: mol of HCO₃²⁻ + mol of HCO₃− = 10.0 mmol + 5.0 mmol = 15.0 mmol The volume of 1.1 M HCl required to reach the second equivalence point is: V = mol of HCl / [HCl] = 15.0 mmol / 1.1 mol/L = 13.6 mL Therefore, the best answer is D.

Question 15

A 25.0 mL sample of 0.10 M sodium benzoate is titrated with 0.10 M HCl(aq). What is the pH after the addition of 32.0 mL of HCl(aq)? (K_b of C₆H₅CO₂^- = 1.6 × 10^-10)

Accepted Answer

Step 1: Write the balanced equation for the reaction between sodium benzoate and HCl:

C6H5COO-Na+ + HCl → C6H5COOH + NaCl

Step 2: Find the number of moles of sodium benzoate present initially:

moles of sodium benzoate = M x V = 0.10 M x 25.0 mL / 1000 mL = 0.0025 moles

Step 3: Determine the limiting reactant:

0.10 M HCl means that there are 0.10 mmol of HCl in 1 mL of solution. Therefore, 32.0 mL of 0.10 M HCl contains:

0.10 mmol/mL x 32.0 mL = 3.2 mmol of HCl

To react completely with the sodium benzoate, 0.0025 moles of HCl is required:

0.0025 moles x 1 HCl / 1 sodium benzoate = 0.0025 moles of HCl

This means that HCl is the limiting reactant.

Step 4: Calculate the moles of benzoic acid produced:

moles of benzoic acid produced = moles of limiting reactant = 0.0025 moles

Step 5: Calculate the concentration of benzoic acid after the addition of 32.0 mL of HCl:

volume of solution = 25.0 mL + 32.0 mL = 57.0 mL = 0.057 L

concentration of benzoic acid = moles of benzoic acid / volume of solution = 0.0025 moles / 0.057 L = 0.044 M

Step 6: Calculate the pH of the solution:

Ka of benzoic acid = 6.5 × 10^-5

benzoic acid is a weak acid, so we can use the expression for the acidity constant to calculate the pH.

Ka = [H3O+][C6H5COO-] /[HC6H5O2]

We assume that initial concentration of benzoate anions is equal to the initial concentration of the sodium benzoate. Thus:

[HC6H5O2] = [NaC6H5O2] = 0.10 M

At equivalence point, the moles of NaC6H5O2 = the moles of NaOH. Therefore, the number of moles of OH- added after the addition of HCl is equal to the number of moles of NaOH required to reach the equivalence point. At the equivalence point:

moles of NaOH = moles of HC6H5O2

0.10 M NaOH means that there are 0.10 mmol of NaOH per 1 mL of solution. Therefore:

0.10 mmol/mL x VmL = 0.0025 moles

VmL = 25.0 mL

So, the volume of NaOH required to reach the equivalence point is 25.0 mL. Since the initial volume of NaC6H5O2 solution is 25.0 mL, the final volume at equivalence point is 50.0 mL. This means that 7.0 mL of 0.10 M NaOH has been added when 32.0 mL of HCl was added. This neutralizes HCl completely and then excess NaOH remains. The moles of the excess OH- can be calculated as:

moles of excess OH- = M x V = (0.10 x 7.0 / 1000) = 7.0 x 10^-3 mol.

Therefore,

[OH-] = moles of excess OH- / volume of solution = 7.0 x 10^-3 mol / 0.057 L = 0.123 M

[H3O+] = Kw / [OH-] = 1.0 x 10^-14 / 0.123 M = 8.13 x 10^-14 M

pH = – log[H3O+] = – log(8.13 x 10^-14) = 1.91

Therefore, the pH after the addition of 32.0 mL of HCl is 1.91, which is option C.

Question 16

What is the concentration of silver(I) ion in a saturated solution of silver(I) carbonate containing 0.0072 M Na₂CO₃? For Ag₂CO₃, K_sp = 8.6 × 10^-12.

Accepted Answer

The answer of What is the concentration of silver(I) ion...

Question 17

What color change is exhibited by phenolphthalein during a titration of aqueous acetic acid with aqueous sodium hydroxide?

Accepted Answer

Phenolphthalein changes from colorless to pink as the solution transitions from acidic to basic, which occurs when acetic acid is neutralized by sodium hydroxide.

Question 18

A solution containing 10. mmol of CO₃²⁻and 5.0 mmol of HCO₃−is titrated with 1.1 M HCl. What volume of HCl must be added to reach the first equivalence point? (1 mmol = 0.001 mol)

Accepted Answer

The answer of A solution containing 10. mmol of CO₃²⁻and...

Question 19

The hydroxide ion concentration of a saturated solution of Fe(OH)₂ is $1.16 \times 10 ^ { - 5 }$ M. What is the solubility product constant for Fe(OH)₂?

Accepted Answer

The solubility product constant $K_{sp}$ for Fe(OH)$_2$ is calculated using the formula $K_{sp} = [Fe^{2+}][OH^-]^2$. Given $[OH^-] = 1.16 \times 10^{-5}$ M, $[Fe^{2+}] = \frac{1.16 \times 10^{-5}}{2}$ M. Thus, $K_{sp} = \left(\frac{1.16 \times 10^{-5}}{2}\right)(1.16 \times 10^{-5})^2 = 7.9 \times 10^{-16}$.

Question 20

Potassium hydrogen phthalate (KHP) is used to standardize sodium hydroxide. If 35.39 mL of NaOH(aq) is required to titrate 0.8246 g KHP to the equivalence point, what is the concentration of the NaOH(aq)? (The molar mass of KHP = 204.2 g/mol) HC₈H₄O₄^-(aq) + OH^-(aq) $\leftrightharpoons$ C₈H₄O₄^2-(aq) + H₂O( $\ell$ )

Accepted Answer

The answer of Potassium hydrogen phthalate (KHP) is used to...

Quiz 18: Principles of Chemical Reactivity: Other Aspects of Aqueous Equilibria

A 25.00-mL sample of propionic acid, HC₃H₅O₂, of unknown concentration was titrated with 0.145 M KOH. The equivalence point was reached when 43.02 mL of base had been added. What was the original concentration of the propionic acid?

The K_sp of Ca(OH) ₂ is 5.5 × 10^-5 at 25 °C. What is the concentration of OH^-(aq) in a saturated solution of Ca(OH) ₂(aq) ?

The concentration of calcium carbonate in a saturated aqueous solution at 25°C is $6.71 \times 10 ^ { - 5 }$ M. What is the K_sp of this sparingly soluble salt?

Which of the following indicators is most suitable for the titration of a 25.00-mL sample of 0.140 M propionic acid, HC₃H₅O₂, with strong base?

The solubility of manganese(II) carbonate is 5.4 × 10^-4 g/L. What is the solubility product constant for manganese(II) carbonate?

Titration of 0.1615 g of an unknown monoprotic acid dissolved in 25.00 mL of water requires 21.84 mL of 0.1231 M NaOH to reach the endpoint. What is the molar mass of the acid?

What is the solubility product expression for La(OH) ₃?

What is the molar solubility of silver(I) iodide at 25°C? The solubility product constant for silver(I) iodide is 8.3 × 10^-17 at 25°C.

What is the pH of a saturated solution of Fe(OH) ₂? (K_sp = 8.0 × 10^-16 and K_w = 1.01 × 10^-14)

The K_sp of BaSO₄ is 1.1 × 10^-10 at 25 °C. What mass of BaSO₄ will dissolve in 1.0 L of water at 25 °C? (molar mass = 233.4 g/mol)

The solubility of strontium carbonate (SrCO₃) in water at 25°C is $4.5 \times 10 ^ { - 3 }$ g/L. What is the K_sp of this sparingly soluble salt?

A solution containing 10. mmol of CO₃²⁻ and 5.0 mmol of HCO₃−is titrated with 1.1 M HCl. What total volume of HCl must be added to reach the second equivalence point? (1 mmol = 0.001 mol)

A 25.0 mL sample of 0.10 M sodium benzoate is titrated with 0.10 M HCl(aq) . What is the pH after the addition of 32.0 mL of HCl(aq) ? (K_b of C₆H₅CO₂^- = 1.6 × 10^-10)

What is the concentration of silver(I) ion in a saturated solution of silver(I) carbonate containing 0.0072 M Na₂CO₃? For Ag₂CO₃, K_sp = 8.6 × 10^-12.

What color change is exhibited by phenolphthalein during a titration of aqueous acetic acid with aqueous sodium hydroxide?

A solution containing 10. mmol of CO₃²⁻and 5.0 mmol of HCO₃−is titrated with 1.1 M HCl. What volume of HCl must be added to reach the first equivalence point? (1 mmol = 0.001 mol)

The hydroxide ion concentration of a saturated solution of Fe(OH) ₂ is $1.16 \times 10 ^ { - 5 }$ M. What is the solubility product constant for Fe(OH) ₂?

Quiz 18: Principles of Chemical Reactivity: Other Aspects of Aqueous Equilibria

A 25.00-mL sample of propionic acid, HC3H5O2, of unknown concentration was titrated with 0.145 M KOH. The equivalence point was reached when 43.02 mL of base had been added. What was the original concentration of the propionic acid?

The Ksp of Ca(OH) 2 is 5.5 × 10-5 at 25 °C. What is the concentration of OH-(aq) in a saturated solution of Ca(OH) 2(aq) ?

The concentration of calcium carbonate in a saturated aqueous solution at 25°C is 6.71×10−56.71 \times 10 ^ { - 5 }6.71×10−5 M. What is the Ksp of this sparingly soluble salt?

Which of the following indicators is most suitable for the titration of a 25.00-mL sample of 0.140 M propionic acid, HC3H5O2, with strong base?

The solubility of manganese(II) carbonate is 5.4 × 10-4 g/L. What is the solubility product constant for manganese(II) carbonate?

Titration of 0.1615 g of an unknown monoprotic acid dissolved in 25.00 mL of water requires 21.84 mL of 0.1231 M NaOH to reach the endpoint. What is the molar mass of the acid?

What is the solubility product expression for La(OH) 3?

What is the molar solubility of silver(I) iodide at 25°C? The solubility product constant for silver(I) iodide is 8.3 × 10-17 at 25°C.

What is the pH of a saturated solution of Fe(OH) 2? (Ksp = 8.0 × 10-16 and Kw = 1.01 × 10-14)

The Ksp of BaSO4 is 1.1 × 10-10 at 25 °C. What mass of BaSO4 will dissolve in 1.0 L of water at 25 °C? (molar mass = 233.4 g/mol)

The solubility of strontium carbonate (SrCO3) in water at 25°C is 4.5×10−34.5 \times 10 ^ { - 3 }4.5×10−3 g/L. What is the Ksp of this sparingly soluble salt?

A solution containing 10. mmol of CO32− and 5.0 mmol of HCO3−is titrated with 1.1 M HCl. What total volume of HCl must be added to reach the second equivalence point? (1 mmol = 0.001 mol)

A 25.0 mL sample of 0.10 M sodium benzoate is titrated with 0.10 M HCl(aq) . What is the pH after the addition of 32.0 mL of HCl(aq) ? (Kb of C6H5CO2- = 1.6 × 10-10)

What is the concentration of silver(I) ion in a saturated solution of silver(I) carbonate containing 0.0072 M Na2CO3? For Ag2CO3, Ksp = 8.6 × 10-12.

What color change is exhibited by phenolphthalein during a titration of aqueous acetic acid with aqueous sodium hydroxide?

A solution containing 10. mmol of CO32−and 5.0 mmol of HCO3−is titrated with 1.1 M HCl. What volume of HCl must be added to reach the first equivalence point? (1 mmol = 0.001 mol)

The hydroxide ion concentration of a saturated solution of Fe(OH) 2 is 1.16×10−51.16 \times 10 ^ { - 5 }1.16×10−5 M. What is the solubility product constant for Fe(OH) 2?

A 25.00-mL sample of propionic acid, HC₃H₅O₂, of unknown concentration was titrated with 0.145 M KOH. The equivalence point was reached when 43.02 mL of base had been added. What was the original concentration of the propionic acid?

The K_sp of Ca(OH) ₂ is 5.5 × 10^-5 at 25 °C. What is the concentration of OH^-(aq) in a saturated solution of Ca(OH) ₂(aq) ?

The concentration of calcium carbonate in a saturated aqueous solution at 25°C is $6.71 \times 10 ^ { - 5 }$ M. What is the K_sp of this sparingly soluble salt?

Which of the following indicators is most suitable for the titration of a 25.00-mL sample of 0.140 M propionic acid, HC₃H₅O₂, with strong base?

The solubility of manganese(II) carbonate is 5.4 × 10^-4 g/L. What is the solubility product constant for manganese(II) carbonate?

What is the solubility product expression for La(OH) ₃?

What is the molar solubility of silver(I) iodide at 25°C? The solubility product constant for silver(I) iodide is 8.3 × 10^-17 at 25°C.

What is the pH of a saturated solution of Fe(OH) ₂? (K_sp = 8.0 × 10^-16 and K_w = 1.01 × 10^-14)

The K_sp of BaSO₄ is 1.1 × 10^-10 at 25 °C. What mass of BaSO₄ will dissolve in 1.0 L of water at 25 °C? (molar mass = 233.4 g/mol)

The solubility of strontium carbonate (SrCO₃) in water at 25°C is $4.5 \times 10 ^ { - 3 }$ g/L. What is the K_sp of this sparingly soluble salt?

A solution containing 10. mmol of CO₃²⁻ and 5.0 mmol of HCO₃−is titrated with 1.1 M HCl. What total volume of HCl must be added to reach the second equivalence point? (1 mmol = 0.001 mol)

A 25.0 mL sample of 0.10 M sodium benzoate is titrated with 0.10 M HCl(aq) . What is the pH after the addition of 32.0 mL of HCl(aq) ? (K_b of C₆H₅CO₂^- = 1.6 × 10^-10)

What is the concentration of silver(I) ion in a saturated solution of silver(I) carbonate containing 0.0072 M Na₂CO₃? For Ag₂CO₃, K_sp = 8.6 × 10^-12.

A solution containing 10. mmol of CO₃²⁻and 5.0 mmol of HCO₃−is titrated with 1.1 M HCl. What volume of HCl must be added to reach the first equivalence point? (1 mmol = 0.001 mol)

The hydroxide ion concentration of a saturated solution of Fe(OH) ₂ is $1.16 \times 10 ^ { - 5 }$ M. What is the solubility product constant for Fe(OH) ₂?