Cells

Question 1

What happens in a galvanic cell?

Answer 1

1) The negative electrode (anode) corrodes due to oxidising

2) The oxidation of the anode cause electrons to be produced and head toward the cathode

3) Electrons are accepted by free roaming ions in the cathodes half cell electrolyte, and these ions collide with the cathode

4) Metal forms on the cathode due to reduction

Question 2

Advantages of Hydrogen Fuel Cell

Answer 2

• High energy conversion efficiency
• Low pollution, hence low greenhouse emission
• No moving parts: Quiet
• Low maintenance
• Can be made a variety of sizes

Question 3

Disadvantages of Hydrogen fuel cells

Answer 3

• Electrodes expensive
• Very little infrastructure
• Sustainability dependent on source of hydrogen
• Storage of hydrogen = problematic

Question 4

Fuel Cells vs Galvanic cells:
What are the similarities?

Answer 4

• Involves spontaneous reactions
• Has electrolyte
• Converts chemical energy to electrical energy

Question 5

Fuel Cells vs Galvanic Cells:
What are the differences?

Answer 5

• Fuel Cell reactants must be continuously supplied
• Fuel cells use porous electrodes to allow diffusion and increase in surface area
• Usually gaseous

Question 6

Does an electrolytic cell convert chemical energy to electrical energy, or electrical energy to chemical energy

Answer 6

• Electrical energy to chemical energy

Question 7

Do Galvanic cells convert chemical energy to electrical energy, or electrical energy to chemical energy

Answer 7

Chemical energy to electrical energy

Question 8

If two electrolytic cells are plugged into the same power supply, the gas produced by the cells is…
Why?

Answer 8

• The same for both anodes
• Same circuit, means same amount of electrons passed through, means same amount of gas

Question 9

Characteristics of primary cells

Answer 9

• Disposable
• Not designed to be recharged

Question 10

Characteristics of secondary cells

Answer 10

• Rechargeable
• Designed to be reused
• Acts as both galvanic and electrolytic cell

Question 11

What way is electron flow in discharge?

Answer 11

• Anode to Cathode

Question 12

What way is electron flow in recharge?

Answer 12

• Anode to Cathode

Question 13

What happens to the cell when changing from discharge to recharge

Answer 13

• The oxidation and reduction reactions swap
• NOT THE POLARITY
• Anode is now on positive side
• Cathode is now on negative side
• Electron flow, as always, from anode to cathode.
• Power source forces electrons into the negative electrode
• Reverses flow of electrons to cause non-spontaneous redox reaction to restore original reactants

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Question 14

What is electrolysis?

Answer 14

• Process of converting electrical energy to chemical energy so non-spontaneous redox reaction can occur.