C10 - Electrolysis (PAPER 1) Flashcards
What is electrolysis
the process of using electricity to extract elements from a compound
What is the name of a positive electrode
anode
What is the name of a negative electrode
cathode
What is an electrolyte
liquid or solution that contains ions and so can conduct electricity
Where are metals formed during electrolysis
cathode
Where are non-metals formed during electrolysis
anode
How can ionic substances be electrolysed
by melting or dissolving them, and then passing a direct current through them
What causes ions to move to the electrodes in electrolysis
the electric current flowing through the electrolyte
Why can solid ionic compounds not be electrolysed
they do not conduct electricity as the ions cannot move
Why are pure elements not always produced in the electrolysis of aqueous solutions
Water can also undergo ionisation
What is the half equation of the ionisation of water
H2O –> H+ + OH-
When is oxygen gas produced during the electrolysis of a solution
- What is the half-equation for this
if no halogen is present
- 4OH- –> O2 + 2H2O + 4e-
What is produced at the anode and cathode during the electrolysis of sodium chloride
2Na+ + 2e- –> 2Na (Anode)
2Cl- –> Cl2 + 2e-
When is hydrogen formed during the electrolysis of a solution
if the metal is more reactive than hydrogen
What metals are extracted using electrolysis from their compounds
ones that are more reactive than carbon
