C3.2 Electrolysis Flashcards
What is electrolysis?
The process of channeling an electric current through a molten or dissolved ionic compound to separate the metal from its compound.
What are the two ion types?
- Cation (-)
- Anion(+)
What is an electrode?
A solid conductor where an oxidation and reduction reaction takes place.
What is oxidation?
Loss of electrons
What is reduction?
Gain of electrons
What is the cathode
Where the metal ions undergo a reduction reaction and are discharged as metal which is extracted
What is the anode
Where the non-metal ions undergo an oxidation reaction and are discharged as a gas or react with the electrode depending on what material is used
How do you reduce the melting point of bauxite (aluminium ore)
Mix the bauxite with cryolite
What electrodes are used in electrolysis of aluminium oxide
graphite electrodes are used because graphite is nonreactive so it wouldn’t affect the experiment
Half equations of aluminium and oxygen
2O 2- → O 2 + 4e -
Al3+ + 3e- → Al
definition of aqueous
It is soluble in water
What other compounds are included in electrolysis of aqueous ionic compounds?
Water molecules are included so apart from cations and anions being present so are OH- ions and H+ ions
What conditions are needed for hydrogen ions to be discharged?
If the metal is more reactive than hydrogen then hydrogen will discharge at the cathode as hydrogen gas instead and vice versa
What conditions are needed for hydroxide ions to be discharged?
If the non-metal is not a halide then hydroxide will be discharged at the anode as oxygen gas or water and vice versa
Half equation for hydrogen
2 H+(aq) + 2e− → H2(g)
