Chemical cells and fuel cells

• What does a cell contain?

  Chemicals which react to produce electricity.
• In a diagram of a cell, what needs to be labelled?

  Voltmeter, positive electrode, negative electrode, electrolyte.
• What is the relationship between cell voltage and reactivity?

  Greater the voltage, greater the reactivity.
• How can you determine the voltage of an unknown cell using voltage data?

  Subtract the voltages of the two metals being used.
• What is a battery?

  Two or more cells connected in series to provide greater voltage.
• How can you work out the voltage of a battery?

  Add up the voltages of all the cells being used.
• Why do non-rechargeable cells eventually stop working?

  The reactants are used up.
• What are alkaline batteries? 


  They are an example of non-rechargeable batteries.
• Why can rechargeable cells be regenerated?

  The chemical reactions are reversed when an external electrical current is supplied.
• Are there any disadvantages to rechargeable cells?

  They require rare resources in manufacture that are finite and they are often recharged using electricity derived from fossil fuels.
• What is a fuel cell?

  A cell which uses a fuel and oxygen to generate electricity.
• What is a hydrogen fuel cell?

  A cell that uses hydrogen and oxygen to generate electrical energy.
• What is the overall reaction word equation for a fuel cell?

  Hydrogen + oxygen --> Water
• What is the overall reaction balanced symbol equation for a fuel cell?

  2H2 + O2 --> 2H2O
• Complete the equation which occurs at the negative electrode of a hydrogen fuel cell H₂ → ___ + ___

  H₂ → 2H++ 2e-
• Complete the equation which occurs at the positive electrode of a hydrogen fuel cell O2 + ___ + ___ --> ____

  O2 + 4H+ + 4e- --> 2H2O
• State three disadvantages of hydrogen fuel cells

  Hydrogen is explosive, mostly produced using fossil fuels and is expensive to store.