Energy and Change

• Heat of Reaction

  (Change in) H
• Exothermic


  
  

  (Change in) H<0

  Energy is released
• Endothermic


  
  

  (Change in) H>0

  Energy is absorbed
• Activation Energy


  
  

  The minimum energy that is required for a reaction to take place.
• Activated Complex


  
  

  The unstable transition state from reactants to products.