3.1.5 Kinetics

Cards (14)

  • Collision theory:
    • Reactions can only occur when collisions take place between particles that have sufficient energy
    • Energy needed to break bonds in reactants
  • Activation energy: the minimum energy which particles need to collide to start a reaction
  • What does the Maxwell-Boltzmann distribution show? the spread of energies that molecules of a gas have at a particular temperature
  • Describe how the Maxwell-Boltzman distribution curve will change when you increase temperature:
    • Total area should remain constant
    • Molecules have a wider range of energies than at lower temperatures
    • Both most probable and mean energy have higher energies
  • Rate of reaction: The change in concentration of a substance in unit time
  • Explain how increasing concentration affect the rate of reaction:
    • More particles per unit volume
    • More frequent collisions
    • Rate of reaction increases
  • What is the effect of increasing temperature on the rate of reaction?
    • Particles have increased kinetic energy
    • Many more particles have E >= Ea
    • Many more successful collisions
    • Significant increase in rate of reaction
  • How does increasing surface area affect the rate of reaction?
    • More particles exposed
    • More frequent collisions
    • Rate of reaction increases
  • Catalyst: Substances that increase reaction rates without getting used up
  • How do catalysts work? They provide an alternative route/mechanism with a lower activation energy
  • Why does lowering activation energy increase the rate of reaction?
    • more particles have energy above activation energy
    • higher frequency of effective collisions
  • Minimum energy in collision theory is called activation energy
  • What must particles do in order to react? Collide with sufficient energy (activation energy) and the correct orientation
  • Do most collisions result in a reaction? no