Electrolysis Flashcards
(21 cards)
Why can’t solid ionic compounds conduct electricity
The ions are locked in place and aren’t free to move because of strong electrostatic forces of attraction
Why can solid ionic compounds conduct electricity when melted or dissolved in water
The forces of attraction are broken and the ions are free to move
What do you call ionic compounds melted or dissolved in water
Electrolytes
What’s the negative electrode called
Cathode and is covered with electrons from the power pack
What’s the positive electrode called
The anode and has a lack of electrons
During the electrolysis of molten ionic compounds what happens
The positive metal ions are reduced in the cathode
And the negative non metal ions are oxidised at the anode
How are metals less reactive than carbon extracted by
By reduction with carbon
How is a metal more reactive than carbon extracted
Electrolysis
Why’s aluminium mixed with cryolite
It lowers the melting point and reduces the the amount of energy needed and saves money
What’s the half equation of aluminium at the cathode
Al³⁺ + 3e⁻ → Al
This is an reduction reaction
What’s the half equation at the anode for oxygen
2O²⁻ → O2 + 4e⁻
This is an oxidation reaction
Why must the anode be replaced regularly
Because since it’s made out of graphite which is a form of carbon
It will react with the carbon molecules produced making carbon dioxide gas
what does passing electricity through electrolytes do?
cause the ions to move to the electrodes
what is electrolysis?
ions discharged at the electrodes making elements
why do we use electrolysis to extract metals?
because the metal is too reactive to be extracted by reduction with carbon or if it reacts with carbon
why is electrolysis expensive
uses large amounts of energy in the extraction process to melt the compounds and make the electricity current
how are the ions in an aq solution discharge
by using inert electrodes depending on the relative reactivity of element
in an aq solution what is produced if the element is more reactive than hydrogen
hydrogen
what is produced on the anode in an aq solution
oxygen unless it contains halide ions when halogen is produced
why is halogen made when halide ions r present in aq solution
because in aq solution water molecules break down making hydrogen ions and hydroxide ions that are discharged
