Electrolysis Flashcards
What does electrolysis loosely translate to
splitting up with electricity
what is done in the process of electrolysis
- electric current is passed through an electrolyte
- ions move towards the electrodes where they react
- reaction causes compound to decompose
what is an electrolyte with examples
- a molten or dissolved ionic compound that can conduct electricity (what you are electrolysing)
- the metal and the non-metal (aluminium oxide)
what happens to the positive ions in electrolysis
positive ions in the electrolyte move towards the cathode and gain electrons (reduced)
what happens to the negative ions in electrolysis
negative ions in the electrolyte move towards the anode and lose electrons (oxidised)
what is a cathode
a negative electrode
what is an anode
a positive electrode
what does the movement of ions in the electrolyte to electrodes result in
the creation of a flow of charge through the electrode
what does the loss or gain of electrons of the ions form and what happens to it
the uncharged element which is discharged from the electrolyte
what is an electrode
a solid that conducts electricity and is submerged in the electrolyte
why cant an ionic solid be electrolysed but molten ionic compounds can
- ionic solids cant be electrolysed because the ions are in a fixed position so they arent free to move
- molten ionic compounds can because the ions can move freely and conduct electricity
what happens to positive metal ions in electrolysis, with a symbol equation as an example
- they are reduced to the element at the cathode
- Pb2+ + 2e- = Pb
what happens to negative non-metal ions in electrolysis, with a symbol equation as an example
- they are oxidised to the element at the anode
- 2Br- = Br2 + 2e- (2e- is the loss of the electrons)
if you want to extract a metal but its too reactive to be reduced with carbon, what method would be used
electrolysis
what are the ecological issues with electrolysis
- very expensive method of extraction
- lots of energy is needed to melt the ore and produce the required current
what is the most important mnemonic to remember when it comes to electrolysis
- OILRIG Oxidisation Is (the) Loss of electrons Reduction Is (the) Gain of electrons
in a setup for electrolysis, which side are the cathodes and anodes on and in what direction are the electrons flowing
- cathode is on the left
- anode is on the right
- electrons flow into the cathode (the the left)
how would you prepare a molten iomci substance to be electrolysed
- put solid ionic substance in a crucible
- the ionic substance will become the electrolyte
- heat the crucible wjth a bunsen burner until the solid is molten
- once solid is molten dip two clean inert electrodes into electrolyte
- connect electrodes to power supply using wires and clips
why should you heat the solid ionic substance with a bunsen burner in a fume cupboard
to avoid releasing any toxic fumes into the room
what are examples of inert electrodes and why are they inert
- graphite or platinum
- they are inert because they are unreactive
how can you check to make sure a current is flowing through the electrodes
put an ammeter or a bulb in series with your circuit to check you have set it up correctly
