5A4 Equilibrium in Ionic Solutions

Question 1

Define:

electrolyte

Answer 1

A substance that conducts electricity when melted or dissolved.

Electrolytes dissociate into ions, allowing electrical current to flow.

Question 2

What type of bonding is typically found in electrolytes?

Answer 2

Ionic bonding

Ionic bonds are characteristic of electrolyte compounds, such as salts and acids.

Question 3

Fill in the blanks:

Ions are electrically charged particles formed when atoms _____ or _____ electrons.

Answer 3

lose, gain

Ions form when atoms lose or gain electrons, resulting in positive or negative charges.

Question 4

List three examples of strong electrolytes.

Answer 4

1. Sodium chloride (NaCl)
2. Potassium chloride (KCl)
3. Sulfuric acid (H₂SO₄)

Strong electrolytes fully dissociate into ions, which contribute to high electrical conductivity.

Question 5

What are weak electrolytes?

Answer 5

Substances that only partially dissociate into ions when dissolved, leading to lower conductivity.

An example is acetic acid (vinegar).

Question 6

Define:

nonelectrolyte

Answer 6

A substance that does not conduct electricity when dissolved or melted.

Nonelectrolytes do not form ions in solution, which prevents them from conducting electricity.

Question 7

List three examples of nonelectrolytes.

Answer 7

1. Sugar (sucrose)
2. Acetone
3. Ethyl alcohol

These compounds do not dissociate into ions, making them nonelectrolytes.

Question 8

How can you test if a substance is an electrolyte or nonelectrolyte?

Answer 8

By setting up an electrical circuit with a battery and measuring the current flow through the solution.

A lightbulb and ammeter help determine whether current flows, indicating electrical conductivity.

Question 9

What is the difference between electrolytes and nonelectrolytes?

Answer 9

Electrolytes dissociate into ions; nonelectrolytes do not.

Nonelectrolytes remain neutral when dissolved.

Question 10

What is the effect of concentration on conductivity?

Answer 10

Higher concentrations of ions lead to greater conductivity.

Strong electrolytes conduct more electricity as their concentration of ions increases.

Question 11

What is the main factor determining the electrical conductivity of a weak electrolyte?

Answer 11

The proportion of dissociated ions in the solution.

Weak electrolytes only partially dissociate, resulting in fewer ions and lower conductivity.

Question 12

True or False:

Urea is a nonelectrolyte.

Answer 12

True

Urea does not dissociate into ions when dissolved, so it is considered a nonelectrolyte.

Question 13

What is an aqueous solution?

Answer 13

A homogeneous mixture in which a substance is dissolved in water.

Electrolytes and nonelectrolytes can both form aqueous solutions.

Question 14

What happens when sodium chloride dissolves in water?

Answer 14

Sodium chloride dissociates into Na⁺ and Cl⁻ ions.

Equation: NaCl(solid) ⇄ Na+(dissolved) + Cl−(dissolved).

Question 15

What is the solubility product constant (Ksp)?

Answer 15

It is the equilibrium constant for the solubility reaction of a solid dissolving in a liquid.

Ksp quantifies how much of a substance can dissolve in a liquid at saturation.

Question 16

Which factor does NOT influence the solubility product constant (Ksp)?

Answer 16

The amount of solid added to the solution.

Ksp is independent of the amount of solid, as only the concentration of ions in solution affects it.

Question 17

How does temperature affect the Ksp value?

Answer 17

Ksp increases with temperature for most solutes.

Temperature affects solubility, thus changing Ksp values.

Question 18

Fill in the blank:

A large Ksp indicates that a substance is _____ soluble.

Answer 18

more

Large Ksp values mean that a substance dissolves well in solution.

Question 19

Define:

molar solubility

Answer 19

It is the number of moles of a substance that can dissolve in 1 liter of solution to reach saturation.

Molar solubility reflects the maximum solute concentration before the solution becomes saturated.

Question 20

True or False:

Ksp can be calculated from ion concentrations.

Answer 20

True

If ion concentrations are known, Ksp can be calculated using the solubility product equation.

Question 21

What does a small Ksp value indicate about a substance’s solubility?

Answer 21

The substance has a low solubility.

A low Ksp means the substance does not dissolve much in solution.

Higher Ksp indicates greater solubility of a substance.

Question 22

List two factors that affect the Ksp value.

Answer 22

1. Temperature
2. pH

Ksp values change with temperature and sometimes pH.

Question 23

What is the Ksp expression for a solubility equilibrium involving a substance dissolving into ions?

Answer 23

Ksp = [A]^x[B]^y

This formula is derived from the reaction AxBy(s)→xA(aq)+yB(aq).

The expression depends on the stoichiometry of the reaction.

The Ksp calculation requires known concentrations of dissolved ions.

Question 24

What ion concentrations are used to calculate Ksp?

Answer 24

The concentrations of the ions in solution, NOT the solid.

Only ions in the aqueous phase are used in the Ksp expression.

Question 25

# True or False: Molar solubility and Ksp are **always directly related**.

Answer 25

False ## Footnote Molar solubility can be calculated from Ksp, but they are not the same value.

Question 26

# Fill in the blank: The solubility product constant (Ksp) represents the **equilibrium between a solid and its** \_\_\_\_\_ in a saturated solution.

Answer 26

ions ## Footnote Ksp is the constant that describes the solubility equilibrium for salts dissolving in water.

Question 27

What is the **common ion effect**?

Answer 27

It is the decrease in solubility of a salt **when a common ion is added** to the solution. ## Footnote Increasing the concentration of one ion can shift the equilibrium, reducing solubility.

Question 28

What **principle** explains the common ion effect?

Answer 28

Le Chatelier’s principle ## Footnote This principle states that reactions will shift to maintain equilibrium when changes occur.

Question 29

Which **ions are involved** in the common ion effect?

Answer 29

Ions that are: * Already present in the solution. * Shared between solutes. ## Footnote The presence of common ions affects the solubility and ionization of compounds.

Question 30

What happens when an **uncommon ion is added** to a solution?

Answer 30

It can increase solubility by creating **favorable ion-ion interactions**. ## Footnote Uncommon ions do not participate in the equilibrium, so they can make the solute more soluble.

Question 31

# True or False: Transition metals **always follow** the common ion effect.

Answer 31

False ## Footnote Transition metals can form complex ions, which may alter their solubility and bypass the common ion effect.

Question 32

What is the **role of ammonia** in the solubility of silver chloride (AgCl)?

Answer 32

Ammonia **forms a complex ion with silver**, increasing its solubility. ## Footnote This is an example of how transition metals can behave differently than other salts in the common ion effect.

Question 33

What happens when chlorine ions are added to **a solution with silver and copper ions**?

Answer 33

**Silver chloride (AgCl) precipitates out**, but copper does not. ## Footnote This is due to the differing solubility product constants (Ksp) of AgCl and copper salts.

Question 34

What does the common ion effect do to the **ionization of weak acids**?

Answer 34

It **decreases** the ionization of weak acids in acidic solutions. ## Footnote The presence of additional hydrogen ions shifts the equilibrium toward the undissociated form.

Question 35

What effect does the common ion have on **weak bases in basic solutions**?

Answer 35

It **decreases** their ionization. ## Footnote The increased concentration of hydroxide ions affects the dissociation of weak bases.

Question 36

List *one* way the common ion effect can be **used in chemistry**.

Answer 36

To selectively **precipitate ions** from a solution. ## Footnote For example, adding chloride ions can separate silver from copper ions.

Question 37

When does the **uncommon ion effect** occur?

Answer 37

When the addition of **ions not involved** in the equilibrium increases solubility. ## Footnote This effect contrasts with the common ion effect by making the system less stable.

Question 38

What is the impact of adding hydrogen ions to **a solution of acetic acid**?

Answer 38

It **reduces** the ionization of acetic acid. ## Footnote The added hydrogen ions shift the equilibrium towards the protonated form of acetic acid, reducing its dissociation.