Colloids

• What is a colloid?

  A mixture with tiny particles evenly spread
• How does a colloid compare to solutions and suspensions?

  • Colloid: 10-1000 nanometers, milky, does not settle (e.g., milk, fog)
  • Solution: 1-10 nanometers, clear, does not settle (e.g., salt in water)
  • Suspension: >1000 nanometers, cloudy, settles (e.g., muddy water)
• What is the appearance of solutions?

  Clear
• What is the particle size range for colloids?

  10-1000 nanometers
• Do colloids settle over time?

  No, they do not settle
• What is the particle size range for solutions?

  1-10 nanometers
• What is the Tyndall effect in colloids?

  Colloids scatter light, making the beam visible
• Do suspensions settle over time?

  Yes, they settle
• How does the Tyndall effect demonstrate the properties of colloids?

  It shows that colloids scatter light visibly
• Do solutions settle over time?

  No, they do not settle
• What does stability refer to in colloids?

  Particles stay dispersed without settling
• What appearance do suspensions typically have?

  Cloudy
• What are the three main properties that characterize colloids?

  • Tyndall effect: Light scattering makes beams visible
  • Brownian motion: Random particle movement keeps them suspended
  • Stability: Particles remain dispersed without settling
• What is Brownian motion in colloids?

  Random movement of particles keeps them suspended
• What are the types of colloids based on their dispersed phase and dispersion medium?

  • Sols: Solid in liquid (e.g., milk, blood)
  • Emulsions: Liquid in liquid (e.g., mayonnaise, lotion)
  • Foams: Gas in liquid (e.g., whipped cream, shaving foam)
  • Aerosols: Solid or liquid in gas (e.g., smoke, dust)
• What is the particle size range for suspensions?

  Greater than 1000 nanometers
• What appearance do colloids typically have?

  Milky or hazy
• Why is stability important for colloids like mayonnaise?

  It keeps the mixture creamy over time
• Why is Brownian motion significant in colloids?

  It prevents particles from settling down
• What are the key characteristics of colloids?

  • Sols: Solid particles in a liquid
  • Emulsions: Liquids dispersed in other liquids
  • Foams: Gases dispersed in liquids
  • Aerosols: Solid or liquid particles in gases
• Why are colloids considered interesting to study?

  • Unique properties like light scattering
  • Applications in various fields (food, medicine)
  • Complex behavior of tiny particles