Topic 20- Eletrode potentials and electrochemical cells Flashcards
What does a more negative electrode potential indicate?
Stronger reducing agent
What are the standard conditions (For hydrogen electrodes)
Solution of H+ at a concentration of 1 mol per dm cubed
298 K (H2 Gas)
100Kpa (H2 Gas)
Platinum electrode
The equation for electrode potential of a cell
E= E(Reduced) - E (Oxidised)
Definition of electrochemical series
List of electrode potentials in numerical order
Equations for lithium batteries
Li + e- ⇌ Li (this side is reversed in overall equation)
Li+ + CoO2 + e- ⇌ Li+ [CoO2]
Advantages of fuel cells
More efficient than combustion engines
Only waste product is water
Can run indefinitely as long as hydrogen and oxygen supplied
Disadvantages of fuel cells
Not actually carbon neutral- energy is used to make oxygen and hydrogen
Hydrogen is highly flammable- dangerous to use.
Why is a platinum electrode used for metals in solution
can carry current
Intert
How to tell a reaction (electrochemical cell) is feasible under standard conditions
It will have a positive overall E0 value
Example of rechargable batteries
Lithium batteries
What is the electrolyte
A medium for ions to travel from one electrode to another
How to tell if negative electrode (anode)
Will be producing electrons (oxidised) (Left hand side)
How to tell if positive electrode (cathode)
Will be absorbing electrons (reduced) (right hand side)
How do batteries recharge
Electrons forced into the system reversing the discharge.
Fuel cell left hand side equation
2H2(g) + 4OH-(aq) –> 4H2O + 4e-
