C5 electricity and chemistry Flashcards
Electrode
A conducting material which passes an electrical current into the substance being electrolysed
Inert
Unreactive
Anode
The electrode connected to the positive terminal in electrolysis. The site of electron loss or oxidation
Cathode
The electrode connected to the negative terminal in electrolysis. The site of electron gain or reduction
Anion
A negative ion which is attracted to the anode
Cation
A positive ion which is attracted to the cathode
Electrolyte
The solution or liquid which surrounds the electrodes, and allows ions to pass through them
Electroplating
A process which used electrolysis to plate one metal (the cathode) With another metal (anode). Useful in purification of metals
Alkali
A chemical which contains or release OH- ions and has a high pH
Why is electrolysis expensive?
The cost of electricity consumed is high
Rules for electrolysis
Cathode: if a metal is more reactive than hydrogen its ions stay in solution and hydrogen is given off. It the metal’s less reactive the metal forms.
Anode: if the solution is concentrated and is a halide, the halogen forms. If the solution is dilute or there’s no halide, oxygen forms.
Electron
Sub-atomic particles which pass the electric current in a circuit
Why don’t ionic substances conduct electricity when they are solid?
The ions are locked in the structure and cannot move to the electrodes
Electrolysis can be used in:
The manufacture of aluminum and other reactive metals
Electroplating
The manufacture of hydrogen, chlorine and sodium hydroxide from salt
Purifying metals
Bauxite
An aluminium ore
