Fuel cells

• What do fuel cells use to produce electrical energy?


  Fuel and oxygen
• How do fuel cells generate electrical energy?


  They use an electrical cell supplied with a fuel and oxidant
• What are the main components of a fuel cell?

  • Fuel
  • Oxidant
  • Electrical cell
• What do fuel cells use to produce electrical energy?


  Fuel and oxygen
• What type of reaction is involved in hydrogen-oxygen fuel cells?

  A redox reaction
• What is the balanced chemical equation for the reaction in hydrogen-oxygen fuel cells?


  $2H₂ +$$O₂ \rightarrow 2H₂O$
• How could hydrogen-oxygen fuel cells be utilized in transportation?


  They could be used in vehicles
• What are the disadvantages of using hydrogen fuel cells?


  • Limited infrastructure for hydrogen production and distribution
  • Storage challenges due to hydrogen's low density
  • High costs of fuel cell technology
• What is the half equation for the reaction of oxygen in a hydrogen-oxygen fuel cell?


  O₂ + 4e⁻ + 2H₂O → 4OH⁻
• What is a fuel cell?


  An electrical cell that uses fuel and oxygen to produce electrical energy.
• How does a fuel cell produce electrical energy?


  It uses energy from the reaction between fuel and oxygen.
• What happens to the fuel when it enters the fuel cell?


  It becomes oxidised and consumes a potential difference within the cell.
• What is an important example of a fuel cell?


  The hydrogen-oxygen fuel cell.
• What are the products of the hydrogen-oxygen fuel cell reaction?


  It produces clean water and releases energy.
• What type of reaction occurs in hydrogen-oxygen fuel cells?

  A redox reaction.
• What is often used as the electrolyte in hydrogen-oxygen fuel cells?


  An acid, such as phosphoric acid.
• What materials are commonly used for the electrodes in hydrogen-oxygen fuel cells?


  Porous carbon with a catalyst.
• Where does hydrogen enter in a hydrogen-oxygen fuel cell?


  Into the anode compartment.
• Where does oxygen enter in a hydrogen-oxygen fuel cell?


  Into the cathode compartment.
• How do the roles of the anode and cathode differ in fuel cells compared to electrolysis?


  In fuel cells, the anode is negative and the cathode is positive.
• What occurs at the anode in a hydrogen-oxygen fuel cell?


  Hydrogen loses electrons to produce H+ ions, which is oxidation.
• What occurs at the cathode in a hydrogen-oxygen fuel cell?


  Oxygen gains electrons and reacts with H+ ions to make water, which is reduction.
• What is the flow of electrons in a hydrogen-oxygen fuel cell?


  Electrons flow through an external circuit from the anode to the cathode.
• What is the overall reaction in a hydrogen-oxygen fuel cell?


  Hydrogen plus oxygen gives water.
• What is the chemical equation for the overall reaction in a hydrogen-oxygen fuel cell?


  $2H_2 +$$O_2 \rightarrow 2H_2O$
• What are the advantages of hydrogen-oxygen fuel cells in vehicles?


  • Produce fewer pollutants (only water and heat)
  • Less toxic waste compared to batteries
  • Rechargeable with a longer lifespan
  • Higher energy storage capacity than batteries
• What are the disadvantages of hydrogen fuel cells?


  • Hydrogen gas requires more storage space
  • Hydrogen is explosive when mixed with air
  • Hydrogen production often relies on fossil fuels or electricity from fossil fuels
• What are conventional fuels for vehicles known for?


  They have a finite supply and are very polluting.
• Why are fuel cell vehicles becoming more popular?


  They offer cleaner energy compared to conventional fuels.
• How do fuel cell vehicles compare to electric vehicles in terms of pollution?


  Fuel cell vehicles produce fewer pollutants than electric vehicles.
• What is a limitation of electric vehicle batteries?


  They have a limit to how many times they can be recharged.
• Why do batteries in electric vehicles need to be recharged more often than fuel cells?


  Batteries store less energy than fuel cells.
• What is a challenge in storing hydrogen fuel?


  Hydrogen is a gas and takes up more space than a rechargeable battery.
• Why is it hard to store hydrogen safely?


  Because hydrogen is explosive when mixed with air.
• How is hydrogen fuel often produced?


  From hydrocarbons or by electrolysis of water.
• What is a common source of electricity used in the electrolysis of water for hydrogen production?


  Electricity generated from fossil fuels.