C6 Electrolysis Flashcards
What is an ion?
The charged particle formed when an atom gains or loses electrons
What is electrolysis?
The breakdown of a substance containing ions using electricity
What is the cathode?
Electrode with a negative charge due to an excess of electrons
What is the anode?
Electrode with a positive charge due to lack of electrons
What does PANIC stand for?
Positive Anode Negative Is Cathode
What is electrolyte?
A liquid containing free moving ions that can be broken down by electrolysis
What is an anion?
A negatively charged ion that is attracted to the anode
What state must electrolyte be in for the ions to move?
Molten or a solution
What is a cation?
A positively charged ion that is attracted to the cathode
Which ore could you extract aluminium from?
Bauxite
What are the advantages of using aluminium over, for example, steel?
Aluminium is more malleable and has a higher strength to weight ratio
What is the first step in extracting aluminium from bauxite?
Purify bauxite (ore) to get Alumina - requires lots of energy
What is the second step in extracting aluminium from bauxite?
Electrolysis of molten Alumina. Cryolite is used to reduce temperature required and save energy and money. Carbon electrodes react with oxygen produced to form carbon dioxide so they need to be replaced regularly
During electrolysis of alumina, why is cryolite used instead of electrolyte?
Cryolite is used to reduce temperature required and save energy and money
Which ions are attracted to the anode?
Negative ions due to opposite charge
How are atoms formed at the anode during electrolysis in aqueous solutions?
In aqueous solutions, group 7 ions are oxidised if present. Otherwise, OH- ions form oxygen molecules
Why does carbon electrodes need to be replaced regularly?
Carbon electrodes react with oxygen produced to form carbon dioxide so they need to be replaced regularly
Which ions are attracted to the cathode?
Positive ions due to opposite charge
How are atoms formed at the cathode during electrolysis in aqueous solutions?
In aqueous solutions the least reactive of the H+ or metal ions are reduced to form atoms
What is electrolysis?
The breakdown of a substance containing ions using electricity
What is the cathode?
Electrode with a negative charge due to an excess of electrons
What is the anodeE?
Electrode with a positive charge due to a lack of electrons
What is electrolyte?
A liquid containing free moving ions that can be broken down by electrolysis
What is an anion?
A negatively charged ion that is attracted to the anode
What is a cation?
A positively charged ion that is attracted to the cathode
What is an ion?
The charged particle formed by the loss or gain of electrons
What is the word equation for neutralisation?
acid + alkali –> salt + water
What is the symbol equation for neutralisation?
H+ + OH- –> H2O
Which energy level diagram has overall negative energy change?
Exothermic
Which energy level diagram has overall positive energy change?
Endothermic
What is an exothermic reaction (in terms of energy level diagrams)?
A reaction in which more energy is used for breaking bonds
What is an endothermic reaction (in terms of energy level diagrams)?
A reaction in which more energy is used for making bonds than breaking them
What do fuel cells produce?
Continuous voltage when supplied with a constant fuel supply and oxygen
What happens in a fuel cell?
Fuel is oxidised to produce electricity
What are simple cells?
Electrolyte and 2 electrodes
What is a battery?
2 joined simple cells
What are the 2 types of batteries?
Alkaline and rechargeable
What is an example of a rechargeable battery?
A Lithium-ion battery
