Topic 5 - Energy Changes. Pt6. Flashcards Preview

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Flashcards in Topic 5 - Energy Changes. Pt6. Deck (11)
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1
Q

What is a fuel cell?

A

electrical cell thats supplied with fuel and oxygen and uses energy from the reaction between them to produce energy efficiently.

2
Q

What happens when fuel enters the cell?

A

it becomes oxidised and sets up potential difference within the cell.

3
Q

Name the different types of fuel cells.

A

Hydrogen-oxygen fuel cell. It produces clean water and releases energy.

4
Q

Explain what happens in a Hydrogen Oxygen fuel cell.

A

Hydrogen goes into the anode compartment and oxygen goes into the cathode compartment.
At the anode hydrogen loses electrons to produce H+ ions. This is oxidation.
H+ ions move to the cathode.
At the positive electrode (cathode) oxygen gains electrons from the cathode and reacts with H+ ions. to make water - this is reduction.
Electrons flow through the external circuit from anode to cathode.
the overall reaction is hydrogen and oxygen which gives you water.

5
Q

Give the half equation for oxidation in the anode,

A

H2 = 2H+ + 2e-

6
Q

Give the half equation for reduction at the cathode.

A

02 + 4H+ + 4e- = 2H20

7
Q

Give the half equation for the overall reaction.

A

2H2 + O2 = 2H2O

8
Q

Advantages of fuel vehicles.

A
dont produce as many pollutants as other fuels.
Operates over a longer time.
Higher efficency than petrol vehicles.
Quieter than combustion vehicles.
Low heat transmission,
9
Q

Disadvantages of fuel cells.

A

Hydrogen is a gas so it takes more room than storing a rechargable battery.
Hydrogen is explosive when mixed with air.
Hydrogen is expensive to produce.

10
Q

Advantages of batteries.

A

Rechargable.

11
Q

Disadvantages of batteries.

A

store less energy need to be recharged frequently.
Limit of how many times its recharged.
More expensive.
Polluting to dipose of.