Fuel Cells Flashcards
Energy Changes (22 cards)
What is a fuel cell?
An electrical cell supplied with fuel and oxygen (or air) that produces electrical energy from their reaction efficiently.
What happens to fuel when it enters a fuel cell?
It becomes oxidised and sets up a potential difference within the cell.
What is an important example of a fuel cell?
Hydrogen-oxygen fuel cell.
What are the by-products of a hydrogen-oxygen fuel cell?
Clean water and energy.
What type of electrolyte is often used in hydrogen-oxygen fuel cells?
Phosphoric acid.
Where does hydrogen go in a hydrogen-oxygen fuel cell?
Into the anode compartment.
Where does oxygen go in a hydrogen-oxygen fuel cell?
Into the cathode compartment.
In a fuel cell, what is the positive electrode called?
Anode.
In a fuel cell, what is the negative electrode called?
Cathode.
What occurs at the anode in a hydrogen-oxygen fuel cell?
Hydrogen loses electrons to produce H⁺ ions (oxidation).
What occurs at the cathode in a hydrogen-oxygen fuel cell?
Oxygen gains electrons and reacts with H⁺ ions to make water (reduction).
What is the overall reaction in a hydrogen-oxygen fuel cell?
2H₂ + O₂ > 2H₂O.
What is produced at the cathode during the reaction?
Water.
What is the flow of electrons in a fuel cell?
From anode to cathode through an external circuit.
True or False: Fuel cell vehicles produce greenhouse gases.
False.
What are the only by-products of fuel cell vehicles?
Water and heat.
How do fuel cells compare to batteries in terms of pollutants?
Fuel cells produce fewer pollutants than batteries.
What are some disadvantages of hydrogen fuel cells?
Hydrogen is a gas, takes up more space to store, is explosive when mixed with air, and production often involves fossil fuels.
Fill in the blank: Hydrogen fuel is made either from hydrocarbons or by _______.
Electrolysis of water.
What is a key advantage of fuel cells over batteries?
Fuel cells can store more energy.
What is the main limitation of rechargeable batteries in electric vehicles?
They have a limit on how many times they can be recharged before needing replacement.
Why are batteries considered more polluting than fuel cells?
They are made from highly toxic metal compounds.
