Diffusion

• What is diffusion?

  Random movement of particles from high to low concentration
• Why does diffusion occur in liquids and gases?

  Particles move randomly from place to place
• What is the process of diffusion until equilibrium?

  • Particles move from high concentration
  • Continue until evenly mixed
  • Achieve equilibrium
• How does temperature affect the rate of diffusion?

  Higher temperature increases the rate of diffusion
• At what temperature does potassium manganate (VII) dissolve fastest?

  90°C
• Why does diffusion occur faster at higher temperatures?

  Particles gain more kinetic energy
• Which diffuses faster, a gas or a liquid?

  A gas diffuses faster than a liquid
• Why do gas particles diffuse faster than liquid particles?

  Gas particles have more energy and move faster
• Describe the diffusion experiment with ammonia and hydrochloric acid.

  • Cotton wool soaked in ammonia and hydrochloric acid
  • Gases meet and react
  • Forms a ring of ammonium chloride
  • Ring is closer to hydrochloric acid end
• Why do ammonia gas particles diffuse faster in the experiment?

  Ammonia particles are smaller
• What does density measure?

  Mass per unit volume
• How are particles arranged in solids?

  Particles are tightly packed together
• What is the density of a gas compared to solids and liquids?

  Gases have low density
• How does the density of liquids compare to solids and gases?

  Liquids have moderately high density
• What is the density of water?

  1 g/cm³
• What happens to materials with density greater than 1 g/cm³ in water?

  They will sink
• What happens to materials with density less than 1 g/cm³ in water?

  They will float