What components does a simple chemical cell have?
- 2 different metals, each dipped into a solution of one of their salts
- A ‘salt bridge’ to allow dissolved ions to pass from one solution to the other
How does a chemical cell work?
A voltage is produced between the 2 metals used in the chemical cell (the further apart the 2 metals are in the reactivity series, the greater the voltage). The chemical cells then store their reactants and when one of them is used up, the reaction stops and a voltage is no longer produced (battery goes ‘flat’).
How does a fuel cell produce electricity?
It needs to be continuously supplied with both a fuel and oxygen from outside, which will react together and produce electricity.
What is different about hydrogen being used as a fuel?
The fuel cell generates electricity and water.
What are the advantages of a hydrogen-oxygen fuel cell?
- Much quieter
- Need less maintenance than a petrol or diesel engine
- Do not produce carbon dioxide (greenhouse gas, contributes to global warming)
What are the differences between fuel cells and chemical cells (batteries)?
- In fuel cells voltage (potential difference) stays the same while the fuel cell is working; the voltage in chemical cells gradually decreases over time with use as the chemicals are being used up
- Fuel cells have large reserves of fuel so they last a long time; chemical cells have small reserves of chemicals so they need to be recharged or disposed of
- Fuel cells cannot be recharged; some types of chemical cells are rechargeable but many are disposable
- Fuel cells are expensive to make; chemical cells are cheap to make
What is a hydrogen-oxygen fuel cell made up of?
Check chemistry book page 125 diagram.
