electrode potential

• What type of reactions do electrochemical cells use?

  Redox reactions
• What creates a flow of electrons in electrochemical cells?

  Electron transfer between products
• What is produced between the two electrodes in an electrochemical cell?

  A potential difference
• What do most electrochemical cells consist of?

  Two solutions with metal electrodes
• What is the function of a salt bridge in an electrochemical cell?

  To carry the flow of charge

  
• What is a half-cell in an electrochemical cell?

  Each solution that makes up the full cell
• What does cell potential indicate in a half-cell?

  How it will react
• What are the specific rules for conventional cell representation?

  • Most negative potential on the left
  • Most oxidised species next to salt bridge
  • Salt bridge shown with a double line
  • Include state symbols
• What is the standard hydrogen electrode used for?

  Measuring standard half-cell potentials

  
• What is the cell potential of the standard hydrogen electrode?

  0.00V

  
• What are the standard conditions for measuring cell potentials?

  1.0 moldm^-3 concentration, 298K, 100 kPa
• What materials are used in the standard hydrogen electrode?

  Hydrochloric acid, Hydrogen gas, Platinum electrodes
• What does a negative cell potential indicate?

  Substances are more easily oxidised
• What does a positive cell potential indicate?

  Substances are more easily reduced
• How do you calculate overall cell EMF?

  Right potential minus left potential

  
• What does a positive overall cell potential indicate about the reaction?

  The reaction is spontaneous and favourable
• What is the anticlockwise rule for combining half-cell reactions?

  1. Write most negative EMF on top
  2. Draw anticlockwise arrows around reactions
  3. Balance electrons on both sides
  4. Write out the cell reaction
• What do very positive electrode potentials indicate?

  Better oxidising agents
• What do very negative electrode potentials indicate?

  Better reducing agents
• How does increasing concentration affect cell EMF?

  Makes cell EMF more positive
• How does increasing pressure affect cell EMF?

  Makes cell EMF more negative
• What types of electrochemical cells are used commercially?

  Non-rechargeable, rechargeable, fuel cells
• What characterizes a rechargeable cell?

  It has a reversible reaction
• What is a common use for lithium ion cells?

  In phones, laptops, and cars
• What electrodes are used in lithium ion cells?

  Lithium Cobalt Oxide and Graphite
• What is required to recharge a cell?

  A current has to be applied
• What is a fuel cell used for?

  To generate electrical current continuously
• What is the most common type of fuel cell?

  Hydrogen fuel cell
• What is produced as the only waste product in hydrogen fuel cells?

  Water
• What are the downsides of hydrogen fuel cells?

  High flammability and expensive production
• What are the differences between non-rechargeable and rechargeable cells?

  Non-rechargeable cells:

  • Reactions are irreversible
  • Cannot be recharged

  
  

  Rechargeable cells:

  • Reactions are reversible
  • Can be recharged