Solutions & Solubility Concepts

Questions and Answers

What effect does an increase in temperature have on the solubility of gaseous solutes in liquid solvents?

It has no effect on their solubility.

It increases their solubility significantly.

It decreases their solubility. (correct)

It causes their solubility to fluctuate randomly.

Which of the following is NOT a colligative property of solutions?

Freezing point

Osmotic pressure

Viscosity (correct)

Boiling point

According to Raoult’s Law, what happens to the vapor pressure of a solvent when a non-volatile solute is added?

It fluctuates based on the temperature.

It decreases. (correct)

It increases significantly.

It remains unchanged.

What is the effect of adding a solute on the freezing point of a liquid?

It decreases the freezing point. Signup and view all the answers

In what scenario do solute molecules require more energy to raise the boiling point of a liquid?

When solute decreases the vapor pressure. Signup and view all the answers

What principle can be used to quantify the change in vapor pressure upon the addition of a solute?

Raoult's Law Signup and view all the answers

Which of the following accurately describes the boiling point of a liquid?

It is defined as the temperature at which vapor pressure equals ambient pressure. Signup and view all the answers

What is the primary difference between a solute and a solvent in a solution?

The solute is dissolved by the solvent. Signup and view all the answers

Which statement correctly describes the relationship between solubility and temperature for solid solutes?

Solubility increases with an increase in temperature. Signup and view all the answers

Which term describes a solution that contains more solute than can normally dissolve at a given temperature?

Supersaturated solution Signup and view all the answers

How is molal concentration defined?

Moles of solute per kilogram of solvent Signup and view all the answers

What is the main characteristic of miscible liquids?

They are soluble in each other in all proportions. Signup and view all the answers

What defines a colloid?

A mixture with one phase dispersed in another but not actually dissolved. Signup and view all the answers

What does parts per million (ppm) measure?

The amount of solute in 1 million parts of solution. Signup and view all the answers

How does solubility generally behave with polar and nonpolar substances?

Polar substances are only soluble in polar solvents. Signup and view all the answers

What defines a saturated solution?

A solution where no more solute can be dissolved at a certain temperature. Signup and view all the answers

What is the ‘heat of solution’ formally defined as?

The energy change that accompanies dissolving one mole of solute in a solvent Signup and view all the answers

Under what condition is the enthalpy of solution considered endothermic?

When the energy required to separate the ions exceeds the energy released in hydration Signup and view all the answers

Which statement correctly describes the impact of pressure on gaseous solutes?

Increased pressure leads to greater solubility of gaseous solutes Signup and view all the answers

What effect do solute particles have on the formation of a crystalline structure in a solid phase?

They inhibit the organization of molecules into a crystalline structure. Signup and view all the answers

Which of the following factors does NOT affect the solubility of a solute?

Pressure for solid solutes Signup and view all the answers

According to Henry's Law, what is the relationship between solubility and partial pressure of gas?

Directly proportional, with a constant, KH Signup and view all the answers

Which expression correctly represents the solubility product constant for an ionic compound with the generic formula MxAy?

Ksp = [M+]^x [A-]^y Signup and view all the answers

What occurs during the separation of ionic substances prior to dissolution?

Energy is consumed, making the process endothermic Signup and view all the answers

What does a low value of the solubility product indicate about a substance's solubility?

The substance is relatively insoluble in the solvent. Signup and view all the answers

Which statement about nonpolar substances is accurate?

Their solubility is favored in nonpolar solvents Signup and view all the answers

In the dissolution of PbCl2, which ions are produced in the aqueous phase?

Pb2+ and Cl- Signup and view all the answers

What is the relationship between osmotic pressure and the number of solute particles in a solution?

Osmotic pressure increases directly with the number of solute particles. Signup and view all the answers

What is a potential outcome of increased temperature on solubility?

May increase or decrease solubility depending on the substance Signup and view all the answers

Study Notes

Terminology

Solution: A homogeneous mixture of one or more solutes uniformly distributed in a solvent; examples include air, which consists of nitrogen, oxygen, and trace gases, showcasing that solutions aren't limited to liquids.
Solute: The dissolved material in a solution, typically present in lesser amounts.
Solvent: The dissolving medium in a solution, generally present in larger amounts.
Molar concentration: Measured in moles per liter of solution.
Molal concentration: Measured in moles per kilogram of solvent, not the total solution.
Percent by weight to volume: Represents grams of solute in 100 mL of solution.
Percent by weight to weight: Represents grams of solute in 100 grams of solution.
Normality: Equivalent concentration per liter; usage has declined in chemistry and medicine.
Parts per million (ppm): Concentration measurement indicating solute amount in one million parts of solution.
Miscible liquids: Liquids that can mix in any proportion, e.g., water and ethyl alcohol.
Immiscible liquids: Liquids that do not mix well, e.g., water and oil.
Colloids: Mixtures where one phase is dispersed in another phase, not fully dissolved.

Solubility

Solubility: Refers to the maximum amount of solute dissolvable in a given solvent at a specific temperature.
Saturated solution: Contains the maximum solute possible under defined conditions.
Supersaturated solution: Contains more solute than a saturated solution, unstable as excess solute can crystallize out.
Polarity principle: Polar solutes are more soluble in polar solvents and nonpolar solutes in nonpolar solvents.

Energy Changes & the Solution Process

Heat of solution: Energy change occurring when a solute dissolves; it’s the enthalpy change for one mole of solute.
Types of enthalpy of solution:
- Exothermic: Energy released during solvation exceeds energy needed for separation.
- Endothermic: Energy required for separation surpasses energy released during solvation.
Ion interaction: Dissolution involves separating ionic compounds and their attraction to solvent molecules influencing overall energy balance.

Factors Affecting Solubility

Pressure impact: Increases in pressure enhance the solubility of gaseous solutes, described by Henry’s Law: (S = KH \times P_{gas}).
Temperature effect: Increased temperature generally raises solubility for solids and liquids but decreases it for gases in liquid solvents.

Colligative Properties of Solutions

Colligative properties: Physical property changes resulting from solute addition include vapor pressure, boiling point, freezing point, and osmotic pressure.
Vapor pressure: Decreases when solute molecules occupy surfaces, quantified by Raoult's Law.
Boiling point elevation: Higher energy is required to raise vapor pressure due to solute introduction.
Freezing point depression: Solute presence disrupts solid crystallization, lowering the freezing point of the solution.
Osmotic pressure: Directly proportional to the number of solute particles present in a solution.

Solubility Product

Solubility product constant (Ksp): Describes the equilibrium concentration of ions in saturated solutions of sparingly soluble ionic compounds.
Ksp formula: (Ksp = [M^+]^x [A^-]^y), where M is cation concentration, A is anion concentration, and x & y represent their stoichiometric coefficients.
Example: For (PbCl_2), the Ksp expression reflects its ionic dissociation: (Ksp = [Pb^{2+}][Cl^-]^2).
Ksp values: Lower values indicate lower solubility of the substance in a solvent.

Studying That Suits You

Use AI to generate personalized quizzes and flashcards to suit your learning preferences.

Description

Explore the fundamental concepts of solutions and solubility in this quiz. Understand key terminology such as solute, solvent, and the nature of homogeneous mixtures. Perfect for students studying chemistry fundamentals.