Separating Mixtures: Solids, Liquids, and Gases

Mixtures and Separation

• A mixture consists of two or more components with different physical properties, but not chemically combined.
• Examples of mixtures:
  • Soil (clay, sand, small pebbles, and plant matter)
  • Suspension (clay or sand mixed with water, opaque)
  • Solution (sugar mixed with water, clear)
  • Emulsion (milk, mixture of water and fatty oil)
• Separating mixtures:
  • Hand sorting (using senses of sight and touch, e.g., separating different types of rocks)
  • Sieving (using different sizes of particles, e.g., separating stones or pebbles from sand)
  • Filtration (using a filter to separate solid particles from a liquid, e.g., separating sand from water)
  • Magnetic separation (using magnetic properties to separate components, e.g., separating mineral ore)

Methods of Separating Mixtures

• Evaporation:
  • Separating a solution by heating the mixture to remove the liquid, leaving the solid behind (e.g., separating salt from seawater)
  • Used to obtain salt in South Africa
• Distillation:
  • Separating two liquids with different boiling points by evaporation and condensation (e.g., separating water and salt in seawater)
  • Uses a still and a Liebig condenser
• Chromatography:
  • Separating colored substances into individual pigments using a solvent (e.g., separating ink into different colors)
  • Used to separate components with different properties, such as solubility and binding to paper

Recycling and Careers in Chemistry

• Recycling:
  • Process of converting waste into new products
  • Examples: metals, plastics, paper, and glass
  • Important for reducing waste and conserving natural resources
• Careers in chemistry:
  • Researcher
  • Laboratory technician
  • Science teacher
  • Environmental chemist
  • Pharmaceutical industry
  • Space exploration
  • Waste management
  • Chemical education/teaching