1. Concentration Terms A. Molarity (M) Definition: Number of moles of solute present in 1 litre of solution. Formula: Where: � = Mass of solute (g) � = Molar mass of solute � = Volume of solution (mL) Important: Molarity changes with temperature because volume changes. B. Molality (m) Definition: Number of moles of solute present in 1 kg of solvent. Formula: Where: � = Mass of solvent (g) Important: Molality is independent of temperature. ⭐ Frequently asked theory question. C. Mole Fraction (x) Key Relation: 2. Solubility & Vapour Pressure A. Henry's Law Statement: The solubility of a gas in a liquid is directly proportional to its pressure. Where: � = Solubility � = Henry's constant � = Pressure B. Raoult's Law For a solution containing two volatile liquids: Where: �, � = Vapour pressures of pure liquids �, � = Mole fractions C. Ideal vs Non-Ideal Solutions Ideal Solution Non-Ideal Solution Follows Raoult's law completely Deviates from Raoult's law ΔV = 0 ΔV ≠ 0 ΔH = 0 ΔH ≠ 0 Example: Benzene + Toluene Shows positive/negative deviation 3. Colligative Properties Definition Properties that depend only on the number of solute particles, not on their nature. A. Relative Lowering of Vapour Pressure (RLVP) For dilute solutions: Where: � = Vapour pressure of pure solvent � = Vapour pressure of solution B. Elevation of Boiling Point Where: � = Ebullioscopic constant C. Depression of Freezing Point Where: � = Cryoscopic constant D. Osmotic Pressure Where: � = Molarity � = 0.0821 L atm K⁻¹ mol⁻¹ � = Temperature in Kelvin Expanded form: 4. Van't Hoff Factor (i) ★ Most Important When solute particles dissociate or associate, the number of particles changes. Formula Non-Electrolytes Do not dissociate. Examples: Urea Glucose Sucrose Strong Electrolytes NaCl MgCl₂ Al₂(SO₄)₃ Degree of Dissociation (α) Where: � = Total ions formed

Molarity (M)

Number of moles of solute present in 1 litre of solution.

Molality (m)

Number of moles of solute present in 1 kg of solvent.

Mole Fraction (x)

The ratio of the number of moles of a component to the total number of moles of all components in a solution.

Henry's Law

The solubility of a gas in a liquid is directly proportional to its pressure.

Raoult's Law

In a solution containing two volatile liquids, the vapor pressure is proportional to the mole fraction of each component.

Ideal Solution

A solution that follows Raoult's law completely, with ΔV = 0 and ΔH = 0.

Non-Ideal Solution

A solution that deviates from Raoult's law, with ΔV ≠ 0 and ΔH ≠ 0.

Relative Lowering of Vapour Pressure (RLVP)

The decrease in vapor pressure of a solvent when a solute is added.

Elevation of Boiling Point

The increase in the boiling point of a solvent due to the presence of a solute.

Depression of Freezing Point

The decrease in the freezing point of a solvent when a solute is dissolved in it.

Osmotic Pressure

The pressure required to stop the flow of solvent into a solution through a semipermeable membrane.

Van't Hoff Factor (i)

A factor that indicates the number of particles the solute breaks into in solution.

Degree of Dissociation (α)

A measure of the fraction of solute that dissociates into ions.