Chapter 6C - Secondary cells Flashcards
(16 cards)
Define Battery
Device consisting of electrochemical cells that convert chemical energy to electrical energy
Define Discharge
Conversion of chemical energy to electrical enegry as a result of a spontaneous reaction.
Define Recharge
Conversion of electrical energy to chemical energy as a result of a non-spontaneous electrolytic reaction.
Define Secondary cell
Rechargeable galvanic cells that can be used many times
What is the role of a seperator?
Seperates the anode and cathode and allows for the flow of ions between electrodes.
What is required to recharge a secondary cell?
- sufficient voltage
- products formed during discharge must remain in contact with the electrode at which they react
Define Battery Life
Number of recharge-discarge cycles before a battery becomes unstable
Describe battery life
- limited
- unwanted physical and chemical changes within the cell
What are the factors impacting battery life?
- loss of products from electrodes
- impurities in the cell
- high temperatures can cause unwanted side reactions
- low temperatures can cause chemicals to crystallise and solidify
What is electroplating?
Process which involves depositing a thin layer of one metal over another by electrolysis
* used for decoration and surface protection
Which electrode does the object being electroplated need to be at?
The negative cathode
Describe the concentration change of solution if anode is made from metal being plated (electroplating)
- ions produced at anode compensate for those being consumed at the cathode
- electrolyte solution will not change.
What does the electrolyte have to be for electroplating?
- A solution of the ion of the metal used for plating
What is an important consideration when using carbon electrodes?
- reacts with oxygen to produce carbon dioxide
- will need replacing from time to time
Define electrorefining
A process of purifying a metal extracted from its ore using electrolysis
NOTE: need to finish
