EXAM 4 CHEM

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

Which of the following statements correctly describe a strong acid-weak base titration curve? Select all that apply.

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

Select all the statements that correctly describe the solubility product constant Ksp for a slightly soluble substance.

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

Which of the following will NOT become more soluble if the pH of the solution is decreased? Select all that apply.

PbCl2 AgBr

Which of the following can affect the solubility of a sparingly soluble ionic compound?

Presence of a common ion Formation of complex ions Solution pH

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

Salts that contain the anion of a weak acid

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.

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

Which of the following salts will dissolve more readily in aqueous nitric acid than in pure H2O? Select all that apply.

Zn3(PO4)2 CaCO3 Fe(OH)3

Select all of the equations that correctly describe the steps required to calculate the concentration of free Ag+ remaining in solution when 0.10 mole of AgNO3 is added to 1.00 L of 0.60 M KCN. Kf for Ag(CN)2- = 1.0 × 1021.

[Ag(CN)2-] = 0.10 M [CN-] = 0.40 M [Ag+][CN−]2[Ag(CN)−2][Ag+][CN-]2[Ag(CN)2-] = 1.0 × 10-21 x(0.40)20.10x(0.40)20.10 = 1.0 × 10-21

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

Consider the reaction PbSO4 (s) ⇌ Pb2+ (aq) + SO42- (aq). When Na2SO4 is added to the system, the presence of the common ion (give the name or formula, including the charge) causes the equilibrium to shift toward the and the solubility of PbSO4 will , in accordance with Le Chatelier's principle.

sulfate,reactants,decrease

Select all the statements that correctly describe a saturated aqueous solution of a slightly soluble ionic compound that is in contact with undissolved solute.

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

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.

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

Which of the following are examples of complex ions?

Fe(SCN)(H2O)52+ HgCl42- Ag(NH3)2+

Which of the following descriptions are correct for an acid-base indicator? Choose all that apply.

The color of the indicator changes over a specific pH range. A typical indicator changes color over a range of about 1.5 - 2 pH units.

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.

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.

The curve for the weak acid-strong base titration rises gradually before the steep rise to the equivalence point. 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.

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

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.

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

Which statement correctly defines the equivalence point in an acid-base titration?

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

In an acid-base titration, the point at which equimolar amounts of acid and base have been combined is called the point.

equivalence

The equilibrium constant Kf is known as the solubilityBlank 1Blank 1 solubility , Incorrect Unavailable constant for a complex ion, and measures the tendency of a metal ion to form a particular complex ion.

formation

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.

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. Listen to the complete question Need help? Review these concept resources.

hydrolosis

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

increase

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, equilibirum, ions

A complex ion consists of a central strongBlank 1Blank 1 strong , Incorrect Unavailable cation covalently bonded to two or more anions or molecules, which act as Lewis

megtal bases

A chemist titrates a 25.00-mL portion of 0.25 M HNO3 with a 0.25 M solution of NaOH. Which of the following options correctly reflect the steps required to calculate the pH once 35.00 mL of NaOH has been added? Select all that apply.

pH = 12.62 Moles of OH- in excess = 2.5 × 10-3 Moles of OH- added = 8.75 × 10-3

For a slightly soluble ionic compound such as Ag2S, the expression Ksp = [Ag+]2[S2-] is called the ____ product constant for the compound.

solubility