Electrolysis Flashcards
Can covalent bonds be separated by electrolysis?
No
Why can’t covalent bond be separated through electrolysis?
Because there is not metal to conduct the electric current and no opposite chargers to attract to different electrodes
What state and why must the substance be to be able to undergo electrolysis?
It must be liquid (molten or dissolved in water) so that the electrons are free
Which electrode do negative ions move towards?
Positive
Which electrode do positive ions move towards?
The negative
What happens at the negative electrode?
The positive ions are reduced (gain their electrons and become normal atoms again)
What happens at the positive electrode?
The negative ions are oxidised (loose electrons and become a normal atom again)
What are electrodes made from and why?
Graphite because it won’t react with the substance
Why can’t electrolysis be done in crystals?
There are no free electrons
How can the substance being dissolved in water effect the products?
Because water forms ions which may effect the end products formed
What happens at the cathode in aqueous solutions?
The most reactive element will be given off as a gas at the cathode
What gas is normally given off at the cathode in aqueous solutions?
Hydrogen
What is electroplating?
Coating an object with a layer of metal through electrolysis
Why are objects electroplated?
- to protect the metal
- to make the object look nice
- to increase surface hardness
What size objects are more expensive to electroplate?
Large
What happens in electroplating?
The object being plated will be placed at the cathode and the anode will be made of the plating metal the solution will be made up of the playing metal
Ions at the cathode will oxidise which will form ions which go into the solution
These negative ions then are attracted to the anode and are reduced and form atoms which are deposited on the object
Why is aluminium oxide used to extract pure aluminium over just using aluminium in electrolysis?
Normal aluminium is too reactive
What is electrolysis?
Where ionic substances are broken down into separate ions
What is gaining electrons known as?
Reduction
What is loosing electrons known as?
Oxidisation
