Chem 113 SB: 18.3, 18.4, 18.5 (acid-base titrations, solubility equilibria, and factors affecting solubility)

Which of the following options correctly describe how to calculate the pH at various stages during the titration of a strong acid against a strong base? Select all that apply. A. Which of the following options correctly describe how to calculate the pH at various stages during the titration of a strong acid against a strong base? Select all that apply. B. Before the equivalence point, [H₃O⁺] = [H₃O⁺]initial - [OH⁻]added. C. At the equivalence point pH = 7.00. D. Initial pH = -log[HA].

C and D C. At the equivalence point pH = 7.00. D. Initial pH = -log[HA].

what are the strong bases?

NaOH LiOH KOH RbOH CsOH Ca(OH)₂ Sr(OH)₂ Ba(OH)₂

what symbol represents molar solubility?

S

Which slightly soluble ionic salts will become more soluble at lower pH?

Salts that contain the anion of a weak acid

formation constant

The equilibrium constant that indicates to what extent complex-ion formation reactions occur

Insoluble bases tend to dissolve in ________ solutions

acidic

Ksp allows us to make quantitative predictions about...

how much of a given ionic compound will dissolve in water

In general, the magnitude of Ksp indicate the solubility of an _________________- the smaller the Ksp value, the _____ soluble the compounds

ionic-compound; less

the larger Kf, the ______ stable the complex ion

more

Select the statements that correctly describe how to calculate the pH at various points during the titration of a weak acid against a strong base. A. Before the equivalence point, pH is calculated by considering the unreacted weak acid only. B. After the equivalence point the pH depends on the concentration of the conjugate base A⁻. C. At the equivalence point the pH calculation is based on the reaction of the conjugate base A⁻ with H₂O. D. The initial [H₃O⁺] is calculated from [HA]init and Ka.

C and D C. At the equivalence point the pH calculation is based on the reaction of the conjugate base A⁻ with H₂O. D. The initial [H₃O⁺] is calculated from [HA]init and Ka.

Which statement correctly defines the equivalence point in an acid-base titration? Multiple choice question. A. The point at which equal volumes of acid and base have been combined B. The point at which the pH of the titration equals 7.00 C. The point at which the number of moles of -OH added equals the number of H+ ions present

C. The point at which the number of moles of -OH added equals the number of H+ ions present

complex ion

Charged species consisting of a central metal cation bonded to two or more anions or polar molecules

When can Ksp values be used to compare the relative solubilities of two ionic compounds?

If the formulas of the compounds contain the same total number of ions

Insoluble acids tend to dissolve in ________ solutions

bases

When Na₂CO₃ is added to a saturated solution of BaCO₃, the equilibrium will shift so as to ______ the quantity of carbonate ions in solution, thus ______ the solubility of BaCO3.

decrease, decreasing

An acid-base indicator is usually a weak organic acid or base for which the _________ and ____________ forms are different colors

ionized; un-ionized

A slightly soluble ionic compound will dissolve to a small extent in H2O and a saturated solution is formed at a fairly _______ solute concentration. At this point there is a(n) __________ between undissolved solid and the dissociated _____________ in solution

low; equilibrium; solute

The anion of a weak acid can be __________ with H⁺

protonated

To make a direct comparison of Ksp values, we must compare _________ with similar ____________

salts; formulas

how many sig figs are used for volume and concentration?

three

True or false: For complex ion formation, a Kf that is >> 1 indicates that a given complex ion is stable, and likely to form.

true

How many sig figs are used for pH?

two

Is a solution with a Q<K saturated or unsaturated?

unsaturated

is it possible to calculate pH at any stage in a titration?

yes

Select all the options that correctly describe the formation constant (Kf) for a complex ion. A. Kf is also known as the stability constant for the complex ion. B. The larger the value for Kf, the more stable the complex ion. C. A complex ion with a large value for Kf will not form easily in solution. D. Kf is equivalent to the solubility product constant.

A and B A. Kf is also known as the stability constant for the complex ion. B. The larger the value for Kf, the more stable the complex ion.

Select all the statements that correctly describe the solubility product constant Ksp for a slightly soluble substance. A. Ksp is a particular form of a general equilibrium constant (Kc). B. The value of Ksp indicates how far a dissolution equilibrium proceeds in favor of dissolved solute. C. Ksp is equal to the solubility for a given ionic compound. D. For a salt of formula AxBy, the Ksp expression is given by [Ay+]^x[Bx+]^y/xy.

A and B A. Ksp is a particular form of a general equilibrium constant (Kc). B. The value of Ksp indicates how far a dissolution equilibrium proceeds in favor of dissolved solute.

Which of the following statements correctly describe the titration curve for the titration of a strong acid with a strong base? Select all that apply. A. The pH rise is very steep close to the equivalence point of the titration. B. The pH rises slowly throughout the titration. C. The equivalence point is at a pH of 7.00. D. The curve starts at a high pH and curves down as base is added.

A and C A. The pH rise is very steep close to the equivalence point of the titration. C. The equivalence point is at a pH of 7.00.

Select all the statements that correctly describe a saturated aqueous solution of a slightly soluble ionic compound that is in contact with undissolved solute. A. An equilibrium exists between the undissolved and dissolved solute. B. There is no undissolved solute in a saturated solution. C. There is a large amount of dissolved solute in a saturated solution. D. The dissolved solute is assumed to be dissociated into ions.

A and D A. An equilibrium exists between the undissolved and dissolved solute. D. The dissolved solute is assumed to be dissociated into ions.

Which of the following statements correctly describe a strong acid-weak base titration curve? Select all that apply. A. Before the equivalence point is reached, the weak base and its conjugate acid are both present in solution. B. Before the equivalence point is reached, only strong base is present in solution. C. The pH at the equivalence point is > 7.00. D. The pH at the equivalence point is < 7.00.

A and D A. Before the equivalence point is reached, the weak base and its conjugate acid are both present in solution. D. The pH at the equivalence point is < 7.00.

Question Mode Multiple Select Question Select all that apply When comparing the titration curve for a weak acid-strong base titration and a strong acid-strong base titration the following differences are found. Choose all that apply. A. The curve for the weak acid-strong base titration rises gradually before the steep rise to the equivalence point. B. The initial pH for the weak acid-strong base titration is lower for the same initial concentration of acid. C. The weak acid-strong base titration curve has a greater pH range over the steep portion. D. The pH at the equivalence point is above 7.00 for the weak acid-strong base titration.

A and D A. The curve for the weak acid-strong base titration rises gradually before the steep rise to the equivalence point. D. The pH at the equivalence point is above 7.00 for the weak acid-strong base titration.

When comparing the titration curve for a weak base-strong acid titration and a strong acid-strong base titration the following differences are found. Choose all that apply. A. The initial pH for the weak base-strong acid titration is higher than that for the same initial concentration of strong base. B. The pH at the equivalence point is below 7.00 for the weak base-strong acid titration. C. The curve for the weak base-strong acid titration drops gradually before the steep drop close to the equivalence point. D. The weak base-strong acid titration curve has a greater pH range over the steep portion.

B. The pH at the equivalence point is below 7.00 for the weak base-strong acid titration. C. The curve for the weak base-strong acid titration drops gradually before the steep drop close to the equivalence point.

what are the strong acids?

HCl HI HBr HNO₃ HClO₃ HClO₄ H₂SO₄

Why does the equivalence point for a weak base-strong acid titration occur at a pH < 7.00?

The conjugate acid of the weak base reacts with H2O to give a solution with pH < 7.00.

Solubility product constant (Ksp)

The equilibrium constant that indicates what extent a slightly soluble ionic compound dissolves in water

solubility

The maximum amount of solute that will dissolve in a given quantity of solvent at a specific temperature

molar solubility

The number of moles of solute in 1 liter of saturated solution

The value of S _________ in the presence of a common ion

decrease

Addition of a common ion generally ____________ solubility

decreases

The solubility of a substance can be expressed in terms of the mass of the substance in _______ present in 1 L of a saturated solution, or in terms of the _______ solubility, which is the number of moles present in 1 L of a saturated solution.

grams; molar

precipitate will form when Qc is _____ than Kc

greater than

The pH at the equivalence point for a weak acid-strong base titration is _____ than 7.00 because at this point the major species in solution is the conjugate _____ of the weak acid. This species reacts with H2O to form a(n) _____ solution.

greater; base; basic

Compared to the curve of the titration of a strong acid with a strong base, the curve for titration of a weak acid with a strong base has a ________ initial pH, a ______ gradual change in pH as base is added, and a _______ vertical region near the equivalence point

higher; more; shorter

Compared to a strong acid-strong base titration, the curve for a weak acid-strong base titration begins at a ______ pH, and has a ______ vertical section as the equivalence point is reached. Multiple choice question.

higher; smaller

At the equivalence point of a weak acid-strong base titration, all the acid has been neutralized. However, the pH of the solution is not 7.0 because of the ___________of the conjugate base to produce OH- ions.

hydrolysis

Adding a strong acid to a slightly soluble ionic compound will _____ its solubility if it contains the anion of a weak acid.

increase

Formation of a stable complex ion will generally ______ the solubility of a sparingly soluble substance.

increase

In general, the effect of complex ion formation is to ___________ the solubility of a substance

increase

For ionic compounds that have the same total number of _____ in their formulas, the larger the Ksp value, the _____ soluble the compound.

ions; more

precipitate will not form when Qc is _____ or ______ Kc

less than or equal to

A complex ion consists of a central ________ cation covalently bonded to two or more anions or molecules, which act as Lewis ___________

metal; bases

We can also use ______________ to determine the value of Ksp

molar solubility

The K expression can change if there are different numbers of...

moles of ions

If a substance has a lower Ksp value, but a larger S value than another substance, it is ________ soluble

more

Many ionic compounds dissolve into ________ ions

more than two

what are the three factors that can affect solubility?

pH adding a common ion formation of a complex ion