Hess' law

• energy in a reaction system

  must be conserved, as it cannot be created or destroyed
• what happens to the overall enthalpy change for a reaction?


  it is the same, regardless of the route taken
• what is Hess' Law used to determine?

  the enthalpy changes for reactions that cannot be found directly using an experimental method
• what do the direction of the arrows indicate?

  whether the values should be added or taken away
• Hess cycle

  
• enthalpy of formation

  
• enthalpy of combustion