Separation of Mixtures

Definition of a Solution

• A solution is a mixture of two or more substances in the same phase.
• Formed when a solute dissolves in a solvent or when miscible liquids are mixed.

Separating Homogeneous Mixtures

• Example: Ethanol and water
  • Evaporation: Used to separate dissolved salt from water by evaporating the water.
  • Simple Distillation: Used to separate ethanol from water by taking advantage of different boiling points (Water: 100°C, Ethanol: 78°C).
    • Ethanol evaporates first, condenses in the condenser, and is collected in the receiving flask.

Homogeneous Mixtures Characteristics

• Components are in the same phase.
• Composition is uniform throughout.

Separating Heterogeneous Mixtures

• Example 1: Sulphur and iron filings

  • Magnetism: Use a magnet to separate iron filings from sulfur.

• Example 2: Salt and sand

  • Salt dissolves in water, but sand does not.
  • Filtration:
    • Add the mixture to water; salt dissolves, sand does not.
    • Filter through paper to separate sand (residue) from saltwater (filtrate).
    • Evaporate water to obtain salt.

• Suspension Separation:

  • Suspension: Mixture of an insoluble solid in a liquid (e.g., chalk in water).

• Example 3: Oil and water

  • Separatory Funnel: Separates immiscible liquids like oil and water using a stopcock to release and stop flow.

Summary

• Various separation techniques depend on whether the mixture is homogeneous or heterogeneous.