Galvanic and Electrolytic Cells
Introduced| English |
|---|
| galvanic cell/ɡælˈvænɪk sel/ |
| electrolytic cell/ɪˌlektrəˈlɪtɪk sel/ |
Turning chemistry into current
- A battery turns a chemical reaction into flowing electrons.
- Run electricity backward, and you force a reaction uphill.
- Both use the same parts, but in opposite directions.
- Redox reactions and wires make the connection.
The galvanic cell
- A galvanic cell 原电池 uses a favourable redox reaction to make electricity.
- Electrons flow through the wire from anode to cathode.
- Oxidation happens at the anode; reduction at the cathode.
Electrons flow through the wire from...
Electrons travel anode to cathode in both cell types.
The electrolytic cell
- An electrolytic cell 电解池 uses electricity to force an unfavourable reaction.
- An outside power source pushes electrons the "wrong" way.
- It is used to plate metals or split compounds.
An electrolytic cell uses electricity to...
An outside source drives a non-spontaneous reaction.
Anode and cathode
- In both cells, oxidation is at the anode and reduction at the cathode.
- Galvanic: the reaction is spontaneous and releases energy.
- Electrolytic: the reaction is forced and consumes energy.
Inside a galvanic cell
Tap each part to trace the electrons and ions in a spontaneous cell.
In both cell types, oxidation occurs at the...
Oxidation is always at the anode.
A galvanic cell runs on a spontaneous reaction; an electrolytic cell forces a non-spontaneous one.
That difference in drive defines the two cell types.
Reduction always occurs at the ____.
Reduction happens at the cathode in both cells.
Is a battery powering a phone a galvanic or an electrolytic cell?
- It uses a spontaneous reaction to supply energy.
- So it is a galvanic cell.
A battery powering a device is which kind of cell?
It uses a spontaneous reaction to supply energy -- galvanic.
In both cells, oxidation is at the anode and reduction at the cathode -- that never changes. What differs is the drive: galvanic is spontaneous (makes current), electrolytic is forced (uses current). And electrons always flow from anode to cathode through the wire.
A galvanic cell turns a spontaneous redox reaction into current, while an electrolytic cell uses current to force an unfavourable one. In both, oxidation is at the anode and reduction at the cathode, and electrons flow anode to cathode -- only the direction of the drive differs.