LESSON 2: Colligative Properties of Solutions & Dilution

Colligative Properties

properties of solution that is quantity-dependent ; concentration-dependent

1. Vapor Pressure Lowering

2. Freezing Point Depression

3. Boiling Point Elevation

4. Osmotic Pressure Elevation

4 Colligative Properties of Solution

Boiling Point Elevation

adding a non-volatile solute lowers the solvent's vapor pressure ; this means a higher temperature is required for the vapor pressure to equal atmospheric pressure, thus raising the boiling point

Molal boiling point elevation constant

K_b

0.512° C/m

Equivalent value for K_b

Freezing Point Depression

solute particles disrupt solvent lattice formation, requiring colder temperatures to freeze

1.86° ⋅ kg/mol

K_f

Van’t Hoff Factor

“i“ ; it represents the number of particles one formula unit of solute produces in solution

Non-Electrolytes

molecular compounds that do not dissociate

Electrolytes

substances that produce electrically conducting solutions when dissolved in a polar solvent (like water) or melted

Strong Electrolytes

dissociate completely into ions making them good conductor of electricity

Weak Electrolytes

dissociate partially into ions making them good conductor of electricity

Dilution

the process of reducing the concentration of a solute in a solution, typically by adding more solvent (such as water) without adding more solute

0°C

Freezing point of pure water

Lower

Freezing point of the solution compared to the pure colvent after a solute is added to pure water

Higher

Boiling point of the solution compared to the pure solvent after a solute was added to pure water

100°C

Boiling point of pure water

Molal freezing point depression constant

K_f