Topic 3- electrolysis Flashcards
What is electrolysis?
The breakdown of a substance using electrolysis.
What three components are needed for electrolysis?
An electrolyte a liquid which contains mobile ions that conduct electricity. Two electrodes made from metal or graphite, which conduct electricity to the electrolyte. An electrical supply and a power pack or battery
What are the two electrodes?
- Cathode-negative electrode
- Anode-positive electrode
During electrolysis what happens at the cathode?
Positive ions gain electrons and become atoms (reduced)
During electrolysis what happens at the anode?
Negative ions lose electrons and become atoms (oxidised)
What are cations in electrolysis?
Positive ions
What are anions in electrolysis?
Negative ions
The ……….. go to the cathode
Cations
The ……………. go to the anode
Anions
What are inert electrodes?
They are electrodes and are not changed in electrolysis. That are usually made from unreactive metals or from graphite.
What is electroplating?
Electroplating is a type of electrolysis that uses non-inert electrodes. The cathode is coated in the metal from the anode
What is important about the electrolytes in electroplating?
They must contain ions from the coating metal
How does electroplating work?
Metal ions from the electrolyte are discharged on the surface of the object. These ions are replaced by metal ions leaving the surface of the anode. To conclude the metal leaves the anode and is deposited into the object until it is completely used up
How is copper purified?
They are purified in a similar way to electroplating except both electrodes are made from copper. The anode is unpure and the cathode is pure. Copper is in the electrolyte The cathode (pure) gains copper atoms while the anode loses copper atoms. Impurities fall off the anode and collect underneath it
