Fuel Cells

Question 1

How does the hydrogen oxygen fuel cell work and what are the advantages over a conventional battery

Answer 1

• uses the reaction of fuel (H2) with O2 to produce a voltage
• The reactants flow in and the products flow out while the electrolyte remains in the cell

Adv

• Fuel cells can operate virtually continuously so long as hydrogen and oxygen continue to flow into the cell
• fuel cells do not have to be recharged

Question 2

What are the two reactions of a hydrogen fuel cell and overall reaction (alkali electrolyte)

Answer 2

1/2 O2 + H2O + 2e -> 2-OH
H2 + 2-OH -> 2H2O + 2e
H2 + 1/2 O2 -> H2O

Question 3

What are the two reactions of a hydrogen fuel cell and overall reaction (acid electrolyte)

Answer 3

H2 -> 2H+ + 2e
1/2O2 + 2H+ + 2e -> H2O
Same as alkali

Question 4

Describe primary cells

Answer 4

1) Non-rechargeable ∴ irreversible
2) redox reactions produce electrical E
3) alkaline based

Question 5

Describe secondary cells

Answer 5

1) rechargeable ∴ reversible

2) lithium ion/ lead-acid

Question 6

Ways H might be stored as fuel for cars

Answer 6

Under pressure
Adsorbed on solid
Absorbed within solid