Chemical Cells and Fuel Cells

Question 1

What does a chemical cell do?

Answer 1

A chemical cell produces a voltage until one of the reactants is used up

Question 2

How do fuel cells work?

Answer 2

They are supplied by an external source of fuel (e.g. hydrogen [most often used in test]) and oxygen or air. The reaction takes place within the fuel cell to produce a voltage. The oxidation of hydrogen results in water being the only product.

2H2 + O2 –> 2H2O

Question 3

What are the advantages of fuel cells?

Answer 3

-They produce only water as waste (no pollutants formed)
-Keeps producing fuel if it keeps being supplied giving a good supply of hydrogen and oxygen gas
-Have a long life compared to other types of cells
-Easy to dispose of at end of life

Question 4

What are the disadvantages of fuel cells?

Answer 4

-Hydrogen is difficult to transport/store as it takes up more storage space than other cells and compressed it is potentially explosive.
It is also dangerous to transport/store as it is explosive when mixed with oxygen
Therefore, it can’t be used in portable devices.
-They are expensive to make
-Hydrogen can be extracted from fossil fuels which are non-renewable
-Carbon dioxide (a greenhouse gas) may be produced in hydrogen’s extraction
-Hydrogen produced by electrolysis is often powered by the national grid, so may not be from a renewable source.