C6 Flashcards
What is electrolysis ?
use of direct electric current to get a chemical reaction.
Whats an electrolyte ?
substance that produces an electrically conducting solution when dissolved
Cathode is ……….
Anode is ………
cathode is negative
anode is positive
why is the anode positive and cathode negative ?
battery pumps electrons away from the anode (postive) and into the cathode (negative)
what happens to positive ions when they reach the electrode
They receive electrons and are reduced .
what happens to negative ions when they reach the electrode
lose electrons and are oxidised .
why can solid ionic compounds not be electrolysed ?
These oppositely charged ions are locked into a rigid structure (cant move) - This structure doesn’t allow the ionic solid to conduct electricity.
why can molten ionic compounds not be dissolved ?
because the atoms cant move + it needs to be disollved to work
what electrode are metals attracted to ?
positive metal ions are attracted to the negative electrode, where they gain electrons and form metal atoms.
what electrode are non metals attracted to ?
Non-metal ions are negative in charge and are, therefore, attracted to the positive anode of the cell.
why is cryolite added to aluminium oxide ?
(is a solvent) reduces some of the energy costs involved in extracting aluminium by allowing the ions in aluminium oxide to move freely at a lower temperature.
whats produced at the anode ?
whats produced at the cathode ?
Oxygen is produced
hydrogen is produced at the cathode
if a metal is more
less reactive than carbon how is it extracted
Metals more reactive than carbon, (e.g aluminium) are extracted by electrolysis, while metals less reactive than carbon (e.g iron) may be extracted by reduction
