Fuel cells

Question 1

Describe the apparatus and method used to make a simple chemical cell.

Answer 1

A piece of zinc dipped in zinc sulfate solution.
A piece of copper dipped in copper sulfate solution.
A piece of filter paper soaked in potassium chloride solution.
Crocodile clips, wires, and a Voltmeter.

1) Electrons flow through from zinc to copper (because zinc is more reactive than copper).
2) Ions pass through the filter paper from one beaker to the other, completing the circuit.
3) The ordinary batteries that you use in torches and clocks are chemical cells, but the solutions are mixed with powders to make a paste.

Question 3

What happens in a hydrogen-oxygen fuel cell?

Answer 3

Hydrogen and oxygen are used to produce a voltage, and water vapour is the only product.

Question 4

What are the advantages and disadvantages of chemical cells?

Answer 4

Advantages:
1) Are suitable for portable appliances.
2) Are cheap to manufacture.

Disadvantages:
1) May contain harmful substances.
2) Do not produce a voltage when one of the reactants is used up - they go ‘flat’.

Question 5

What are the advantages and disadvantages of hydrogen-oxygen fuel cells?

Answer 5

Advantages:
1) Produce water as the only waste.
2) Produce a voltage as long as the fuel and air are supplied.

Disadvantages:
1) Are not suitable for portable appliances.
2) Are expensive to manufacture.