Is Matter Around Us Pure

• Introduction to Matter

  • What is Matter?
    • Anything that occupies space and has mass.
  • Classification of Matter
    • Pure Substances
      • Made of only one type of particles.
      • Fixed properties.
    • Mixtures
      • Made of two or more pure substances.
      • Variable composition.

• Types of Mixtures

  • Homogeneous Mixtures
    • Uniform composition throughout.
    • Examples: Salt in water, Sugar in water, Alloys.
  • Heterogeneous Mixtures
    • Non-uniform composition.
    • Examples: Oil and water, Sand and salt, Suspensions.

• Solutions (Homogeneous Mixtures)

  • Components of a Solution
    • Solute: Substance dissolved (minor component).
    • Solvent: Medium in which solute dissolves (major component).
  • Types of Solutions based on Saturation
    • Unsaturated Solution: More solute can be dissolved.
    • Saturated Solution: Maximum amount of solute dissolved at a given temperature.
    • Solubility: Amount of solute present in a saturated solution at specific temperature.
  • Concentration of Solutions
    • Mass by Mass Percentage = $\frac{\text{Mass of Solute}}{\text{Mass of Solution}} \times 100$
    • Mass by Volume Percentage = $\frac{\text{Mass of Solute}}{\text{Volume of Solution}} \times 100$

• Suspensions and Colloids

  • Suspensions
    • Heterogeneous mixture.
    • Particles are visible to the naked eye.
    • Scatters light (beam becomes visible), settles down over time.
  • Colloidal Solutions
    • Appears homogeneous but is heterogeneous.
    • Particles are very small, do not settle down.
    • Exhibits Tyndall Effect (scattering of light).
    • Components: Dispersed phase and Dispersion medium.
    • Examples: Milk, Fog, Smoke, Blood.

• Separation of Mixtures

  • Evaporation
    • Separates volatile component (solvent) from non-volatile solute (e.g., salt from water).
  • Centrifugation
    • Based on density using a centrifuge (e.g., cream from milk).
  • Separating Funnel
    • Separates immiscible liquids (e.g., oil and water).
  • Sublimation
    • Separates sublimable volatile component from non-sublimable impurities (e.g., camphor and salt).
  • Chromatography
    • Separates solutes that dissolve in the same solvent (e.g., colors in black ink, pigments from plant extract).
  • Distillation & Fractional Distillation
    • Distillation: Separates miscible liquids with large boiling point difference.
    • Fractional Distillation: Separates miscible liquids with boiling point difference less than 25K (e.g., gases from air, petroleum fractions).
  • rystallization
    • Purifies solids from solution (e.g., pure alum from impure sample).

• Pure Substances

  • Elements
    • Basic form of matter that cannot be broken down by chemical reactions.
    • Classified into:
      • Metals: Lustre, malleable, ductile, good conductors (e.g., Iron, Gold).
      • Non-metals: Brittle, poor conductors, various colors (e.g., Oxygen, Carbon).
      • Metalloids: Intermediate properties between metals and non-metals (e.g., Silicon, Boron).
  • Compounds
    • Substance composed of two or more elements chemically combined in a fixed proportion.
    • Properties are entirely different from its constituent elements (e.g., Water - $H_2O$, Carbon Dioxide - $CO_2$).

• Physical vs Chemical Changes

  • Physical Change
    • No new substance formed.
    • Temporary and reversible.
    • Changes in physical properties (e.g., Melting of ice, Boiling of water).
  • Chemical Change
    • New substance formed with different chemical properties.
    • Permanent and usually irreversible (e.g., Burning of paper, Rusting of iron).