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Chemical cells for AQA GCSE Chemistry
This page covers the following topics:
1. Chemical cells
2. Fuel cells
A chemical cell is a system that uses chemical reactions to create a potential difference across its electrodes. The voltage created at the cell is influenced by the the reactions happening in a cell and electrodes used. For example, the further away in the reactivity series a reduced metal is from the oxidised metal, the greater voltage is created.
Two separate redox reactions within solutions can be linked with a salt bridge to create a cell. The salt bridge completes the circuit by providing relevant ions to the solution it connects. Multiple cells can be combined to produce a battery that can have a higher potential difference across its electrodes. Once a non-rechargeable battery runs out of reactants in its cells, it cannot be reused by recharging, but it still may be recycled.
A fuel cell is a system that uses energy released during a combustion reaction to create a potential difference. During the combustion of hydrogen water steam is produced that causes little to no harm to the environment. During the combustion of fossil fuels within fuel cells, not only water but also greenhouse gas CO₂ is produced, which is not environmentally friendly. Since the process of producing fuel from the products of combustion is more complex that just recharging a battery using electricity, fuel cells are non-rechargeable. Fuel cells have an increased safety risk as the fuel may react with oxygen at any point causing an explosion.
1
Two separate redox reactions within solutions can be linked with a salt bridge to create a cell. Explain the function of the salt bridge.
The salt bridge completes the circuit by providing relevant ions to the solution it connects.
completing the circuit by providing ions
2
Name two main factors that affect the voltage created by a chemical cell.
The voltage created at the cell is influenced by the the reactions happening in a cell and electrodes used.
reactions, electrodes
3
Provide a safety risk associated with using fuel cells.
Fuel cells have an increased safety risk as the fuel may react with oxygen at any point causing an explosion.
explosion when reacting with oxygen
4
Describe a non-rechargeable battery.
Once a non-rechargeable battery runs out of reactants in its cells, it cannot be reused by recharging, but it still may be recycled.
A non-rechargeable battery cannot be reused after running out of reactants.
5
Explain how using a fuel cell based on ethane can contribute towards the global warning.
During the combustion of fossil fuels within fuel cells, not only water but also greenhouse gas CO₂ is produced, which is not environmentally friendly.
Produced CO₂ is a greenhouse gas.
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