2.2 - Rates of Reaction

• Define activation energy:

  The minimum energy that a particle needs in order to react: the energy (enthalpy) difference between the reactants and the transition state
• Define catalyst:

  A substance that increases the rate of a reaction without being used in the process. It provides an alternative route with a lower activation energy
• Define heterogeneous catalyst:

  A catalyst in a different phase from the reactants
• Define homogenous catalyst:

  A catalyst in the same phase as the reactants
• Define reaction rate:

  Change in the concentration of a reactant or product per unit time
• What is collision theory?

  Collision theory is a theory that explains how chemical reactions occur by stating that reactions can only happen when particles collide with sufficient energy and proper orientation.
• What three factors affect the rate of reaction?

  1. Increasing temperature
  2. Increasing concentration/pressure
  3. Increasing surface area
  4. Addition of a catalyst
• Give the rate of chemical reaction equation?

  Rate = change in concentration/time, with units mild$^{-3}$s$^{-1}$
• Is the breaking of bonds exothermic or endothermic?

  Exothermic
• Catalysts are inert in reactions, meaning:

  They do not participate, and are therefore not used up