15. Electrochemical Cells Flashcards
What is an electrochemical cell?
An arrangement that produces electricity through a chemical reaction
What are advantages of using an electrochemical cells rather than mains electricity?
- safety
- portability
What are disadvantages of using an electrochemical cells rather than mains electricity?
- voltage limitations
- cost
- need replaced or recharged
What is the set up for a simple electrochemical cell?
What is an electrolyte?
What is the purpose of the electrolyte?
To complete the circuit
Where does the reaction(s) take place in an electrochemical cell?
On the surfaces of the electrodes (metal strips)
In which direction do the electrons flow in an electrochemical cell?
From the metal higher in the electrochemcial series to the metal lower
Why is the flow of electrons through the wire lower than it should be in a simple cell?
The metal electrode that is losing electrons is in direct contact with the aqueous ions accepting them allowing direct displacement
How do we eliminate the possibility of direct displacement in an electrochemical cell?
We use a “half cell” arrangement.
What is the basic half cell arrangement using 2 metals?
2 metals sit in solutions containing their own ions. Both these solutions are joined by a salt (or ion) bridge
Why do cells “run out” and stop working?
The redox reaction stops due to chemicals running out.
What are the 2 purposes of the salt (ion) bridge in a half cell arrangement
- To complete the circuit
- To maintain the charge balance in the cell
