Chemical cells and fuel cells

Question 1

what is a battery comprised of?

Answer 1

multiple cells

Question 2

what do chemical cells do?

what do we say when it runs out?

Answer 2

produce a voltage until one of the reactants is used up

the battery had gone ‘flat’

Question 3

how are fuel cells different to chemical cells?

Answer 3

produce a voltage continuously, as long as they are supplied with:

a fuel
oxygen (from the air)

Question 4

how does a hydrogen-oxygen fuel cell work?

what is the only product from this reaction?

Answer 4

hydrogen and oxygen are used to produce a voltage.

Water is the only product.

Question 4

what is the overall reaction in a hydrogen-oxygen fuel cell? (word and symbol)

Answer 4

Hydrogen + oxygen → water

2H2(g) + O2(g) → 2H2O(l)

Question 5

why are fuel cells useful for use in spacecrafts or vehicles? (3)

Answer 5

they have no moving parts to maintain
they are small for the amount of electricity they produce
the water they produce is useful as drinking water

Question 6

what are the strengths and weaknesses of using fuel cells in vehicles? (5)

Answer 6

strengths:
Quiet in use
only waste product is water
fewer moving parts

weaknesses:
Hydrogen is more difficult to store
few filling stations

Question 7

what are strengths and weaknesses of using petrol/diesel in a vehicle? (5)

Answer 7

strengths:
Petrol and diesel are easier to store
thousands of filling stations

weaknesses:
Noisy in use
carbon dioxide is a waste product
many moving parts

Question 8

what is a problem with the state of hydrogen? (hint: storing) (2)

Answer 8

-Hydrogen, diesel and petrol are all highly flammable fuels,
-but hydrogen is more difficult to store because it is a gas and the other fuels are liquids

Question 9

Suggest a reason that explains why the quietness of fuel cell vehicles may be a weakness.

Answer 9

Pedestrians may not hear the vehicle coming, and so they may be more likely to be run over when crossing the road.