Energy Transfers - Fuel Cells

Question 1

Why are fuel cells used in space crafts?

Answer 1

• Produces drinking water
• Lightweight, have more storage
• Compact
• No moving parts

Question 2

Why is the car industry developing fuel cells?

Answer 2

• No CO2 emissions
• Doesn’t use up fossil fuels
• Main product is water which is not a pollutant
• Large source of hydrogen available by decomposing water

Question 3

What are the advantages of fuel cells?

Answer 3

• Direct energy transfer as it doesn’t need to be converted into heat first
• This makes them more efficient
• No pollutants such as nitrogen oxides
• Last longer than rechargeable batteries before they need to be replaced
• Weigh less than current batteries

Question 4

What are the disadvantages of fuel cells?

Answer 4

• They use poisonous catalysts which will have to be disposed of at the end of a fuel cells life
• Fossil fuels are burnt to produce the hydrogen and oxygen needed

Question 5

How do we get energy from fuel cells?

Answer 5

The fuel reacts with oxygen in the air and the reaction is exothermic.

Question 6

What is the reaction in a hydrogen fuel cell?

Answer 6

• 2H2 + O2 —> 2H2O
• When the hydrogen reacts with the oxygen by burning the chemical energy given out is heat
• The fuel cell converts the energy straight into electrical energy so there is no heat

Question 7

What happens at the cathode in a fuel cell?

Answer 7

• Oxidation

- 2H2 —> 4H^+ + 4e^-

Question 8

What happens at the anode in a fuel cell?

Answer 8

• Reduction

- 4H^+ + O2 + 4e^- —> 2H2O