CR

Water, Mixtures, pH, and Metabolic Reactions

Mixtures: definitions and types

  • Mixture: substances blended but not chemically combined; no bonding between substances.
  • Three kinds of mixtures differ by particle size and uniformity:
    • Solution: homogeneous mixture with very small solute particles; usually transparent; light passes through; particles not visible; can pass through semipermeable membranes.
    • Colloid: heterogeneous mixture with intermediate particle size; particles may be visible under certain conditions and can gel or become cloudy; often involves proteins; may scatter light (tyndall effect).
    • Suspension: heterogeneous mixture with large particles that tend to settle out over time; can be opaque.
  • Example discussed: emulsion is a type of suspension where one liquid is dispersed in another (e.g., fat in water).