Fuel Cells

Question 1

How are fuels cells provided with fuel ?

Answer 1

From an external source of fuel (eg hydrogen) and oxygen from the air

Question 2

How does the fuel cell generate electricity ?

Answer 2

By reacting hydrogen with oxygen
The fuel is oxidised electrochemically within the fuel cell to produce a potential difference

Question 3

What can hydrogen fuel cells be used for ?

Answer 3

To power cars

Question 4

What is the waste product produced by hydrogen fuel cells ?

Answer 4

No pollutants only water

Question 5

Write the half equation, at the negative anode, for Hydrogen?

Answer 5

2H2 ——> 4H+ + 4e-

Hydrogen is oxidised

Question 6

Write the half equation for oxygen at the cathode?

Answer 6

O2 + 4H2 + 4e- ——> 2H2O

Question 7

What happens to hydrogen?

Answer 7

It is oxidised which produces water

Question 8

Why are some pros of hydrogen fuel cells ?

Answer 8

• run for alsong as you provide them with hydrogen
• do not get less efficient as they run
• can be a source of drinkable water

Question 9

What are some cons of rechargeable batteries ?

Answer 9

• will run out and need to be recharged
• store less electricity the more charging cycles they go through meaning they need replacing

Question 10

What are some cons of hydrogen fuel cells ?

Answer 10

• run off hydrogen which can be explosive and is very difficult to store safely
• produce a low potential difference or voltage so several are needed

Question 11

What are some pros of rechargeable fuel cells ?

Answer 11

• no dangerous fuels are required
• can produce a greater potential difference than hydrogen fuel cells