Kinetics

• What is activation energy?

  Minimum amount of energy a molecule needs to have for a successful collision to occur.
• What is the rate of reaction?

  The rate at which the molar concentration of a reactant or product changes per unit time.
• Why does increasing the concentration increase the rate of reaction?

  There are more reactant molecules per unit volume. This results in there being more successful collisions per unit time.
• What is increasing the pressure the same as?

  Decreasing the volume.
• Why does increasing the pressure increase the rate of reaction?

  The reactant molecules are closer together in a smaller volume so there will be more successful collisions per unit time.
• Why does increasing the surface area (decreasing the particle size) increase the rate of reaction?

  It reveals more surface molecules for the other reagent to react with. This results in more successful collisions per unit time.
• Why does increasing the temperature increase the rate of reaction?

  Many more molecules have energy greater than the activation energy. This results in many more successful collisions per unit time.
• What is a catalyst?

  A substance that speeds up/ increases the rate of a chemical reaction and is recovered chemically unchanged at the end.
• How does a catalyst work?

  Provides an alternative reaction pathway with lower activation energy.
• What happens after adding a catalyst?

  Many more molecules have energy greater than the activation energy.
• Why does the Maxwell-Boltzmann distribution curve start at the origin?

  There are no molecules with zero energy.
• What does the area under the Maxwell-Boltzmann distribution curve represent?

  The number of molecules in the sample.