Lecture: Chapter 14a - Types of Solutions

Key Topics

• Homogeneous Mixtures
• Colloids and Suspensions
• Special types of solutions relevant to human body and medicine

Homogeneous Mixtures

• Previously discussed as solutions.
• Example: Solid dissolving into ions completely and evenly in water.

Colloids

• Definition: Homogeneous mixtures with bigger particles.
• Examples: Fog, clouds, dust, smoke, marshmallows, whipped cream, mayonnaise, milk, gelatin, blood plasma, paints.
  • Fog and clouds: liquid droplets in gas.
  • Dust and smoke: solid particles in gas.
  • Whipped cream and milk: visible particles under microscope.
• Properties: Particles are bigger but small enough to mix evenly.

Suspensions

• Definition: Mixtures that start homogeneous but turn heterogeneous over time.
• Examples: Medications like suspensions, juices with pulp, smoothies.
  • Medical relevance: Need to shake suspensions before use as medication settles.
• Properties: Larger particles, settle over time, turning mixture heterogeneous.

Comparison: Solution, Colloid, Suspension (S-C-S)

• Particle Size:
  • Solution (smallest)
  • Colloid (medium)
  • Suspension (largest)
• Settling:
  • Solutions: Particles do not settle.
  • Colloids: Particles do not settle.
  • Suspensions: Particles settle rapidly.
• Separation: Will be covered in more detail later.

Particle Size Details

• Solution: Particles < 1 nanometer.
  • Includes atoms, small molecules, ions.
• Colloid: Particles larger than individual atoms/ions but smaller than 100 nanometers.
  • Includes large molecules like protein, glucose.
• Suspension: Particles > 100 nanometers.
  • Liquid cannot suspend particles; they settle.

Additional Notes

• Importance of particle size in defining solutions, colloids, and suspensions.
• Colloids and suspensions have practical applications in medicine and daily life.