Fuel cells Flashcards
1
Q
What is a battery?
A
- two or more cells connected in series
1
Q
What is a simple cell?
A
- connecting 2 different metal electrodes in contact with electrolyte
- greater difference in reactivity = greater voltage
- more reactive metal = negative electrode
- less reactive metal = positive electrode
- electrons flow from negative to positive electrode
2
Q
Why does a rechargable battery go flat?
A
- reactants in battery are used up
- reaction cannot be reversed
3
Q
Why are rechargable batteries rechargable?
A
- when external current is applied reaction reverses
4
Q
What are the disadvantages of hydrogen fuel cells?
A
- expensive to produce
- extremely flammable, hard to store
- fossil fuels may be used to produce hydrogen
5
Q
What are the advantages of hydrogen fuel cells?
A
- cheap to maintain, no moving parts that would eventually wear out
- only waste product = water
- never goes flat as long it as a continous fuel supply
6
Q
What do fuel cells need to produce a voltage?
A
- fuel and oxygen
7
Q
What is the equation for a hydrogen fuel cell?
A
2H2 (g) + O2 (g) -> 2H2O
8
Q
How do you work out an ionic equation?
A
1) add the half equations together
2) make sure that it is balanced
3) cancel the electrons
9
Q
A
