Energy changes

• What is this reaction profile?

  Endothermic

  
• What is this reaction profile?

  Exothermic

  
• what is a hydrogen cell?

  Fuel cell
• How does a fuel cell work?

  Electrochemical reaction.
• What is an electrochemical reaction?

  Chemical transformation involving the transfer of electrons.
• What do we use fuel cells for?

  Electricity
• Why do we use hydrogen fuel cells?


  Efficiency, don’t contribute to climate change
• How do hydrogen fuel cells work?

  Electrolysis.
• What electrolysis takes place within a hydrogen fuel cells?

  Hydrogen oxidation.
• How do you work out bond energies?


  Bonds broken - bonds made
• What does a positive bond energy calculation mean?


  That’s it’s an exothermic reaction
• What does it mean if your bond energy total is negative?

  Then it’s endothermic