Colligative Properties of Nonvolatile Solutes

Questions and Answers

What are the four main colligative properties?

Boiling point elevation (correct)

Osmotic pressure (correct)

Vapor pressure lowering (correct)

Freezing point depression (correct)

What is boiling point elevation (∆Tb)?

The boiling point of the solution (Tb) minus the boiling point of the pure solvent (T°b): ∆Tb = Tb - T°b

What is ∆Tb proportional to?

Concentration: ∆Tb = Kb m

What is freezing point depression (∆Tf)?

The freezing point of the pure solvent (T°f) minus the freezing point of the solution (Tf): ∆Tf = T°f - Tf Signup and view all the answers

What is ∆Tf proportional to?

Concentration: ∆Tf = Kf m Signup and view all the answers

What is the van't Hoff factor, i?

It equals the number of ions produced from each molecule of a compound upon dissolving. Signup and view all the answers

What is the equation for boiling point elevation and freezing point depression for compounds that dissociate?

∆Tb = iKb m and ∆Tf = iKf m Signup and view all the answers

What is osmosis?

The passage of solvent through a semipermeable membrane from the less concentrated side to the more concentrated side. Signup and view all the answers

What is osmotic pressure?

The amount of pressure necessary to cause osmosis to stop. Signup and view all the answers

What is the osmotic pressure formula?

P = MRT Signup and view all the answers

What is an isosmotic solution?

A solution that has the same osmotic pressure as the solution inside the cell. Signup and view all the answers

What is a hyperosmotic solution?

A solution that has a higher osmotic pressure than the inside of the cell. Signup and view all the answers

What is a hyposmotic solution?

A solution that has a lower osmotic pressure than inside the cell. Signup and view all the answers

Study Notes

Colligative Properties of Nonvolatile Solutes

Four main colligative properties: vapor pressure lowering, freezing point depression, boiling point elevation, and osmotic pressure.

Boiling Point Elevation

Defined as the difference between the boiling point of the solution (Tb) and the boiling point of the pure solvent (T°b): ∆Tb = Tb - T°b.
Directly proportional to the concentration of the solute, described by the formula: ∆Tb = Kb m, where Kb is the molal boiling-point elevation constant.

Freezing Point Depression

Defined as the difference between the freezing point of the pure solvent (T°f) and the freezing point of the solution (Tf): ∆Tf = T°f - Tf.
Also directly proportional to the concentration of the solute, shown by the equation: ∆Tf = Kf m, where Kf is the molal freezing-point depression constant.

Van't Hoff Factor (i)

Represents the number of ions produced from each molecule of a compound when it dissolves in a solution.
For dissociating compounds, the formulas for boiling point and freezing point become: ∆Tb = iKb m and ∆Tf = iKf m.

Osmosis

The process whereby solvent molecules pass through a semipermeable membrane from a less concentrated solution to a more concentrated one.

Osmotic Pressure

Defined as the pressure required to prevent osmosis from occurring.
Calculated using the formula: P = MRT, where P is osmotic pressure, M is molarity of the solute particles, R is the gas constant, and T is the temperature in Kelvin.

Types of Osmotic Solutions

Isosmotic solution: Has the same osmotic pressure as the solution inside a cell, resulting in no net water flow into or out of the cell.
Hyperosmotic solution: Exhibits higher osmotic pressure than the cell interior, causing water to move out of the cell, leading to cell shrinkage.
Hyposmotic solution: Shows lower osmotic pressure compared to the inside of the cell, causing water to enter the cell and resulting in cell swelling.

Description

This quiz covers the key concepts of colligative properties associated with nonvolatile solutes, including vapor pressure lowering, freezing point depression, boiling point elevation, and osmotic pressure. Each definition provides essential insights into how these properties are measured and calculated in solutions.