Topic 9.2 - Electrochemical cells Flashcards
Electrolysis (E)
Using direct current (DC) to decompose an electrolyte. Ions must be molten or aqueous (free to move)
Electrolyte (E)
Molten/aqueous ionic substances that are decomposed during electrolysis
Anode (E)
Has a positive charge, anions come here to be oxidised. Electrons move from the anode to the cathode through the wires and the cell.
Cathode (E)
Has a negative charge, cations come here to be reduced. Electrons move into the cathode from the anode through the wires and the cell.
CNR
Electrolytic cell (E)
Convert electrical energy to chemical energy by bringing about non-spontaneous processes (battery required)
Voltaic cell (V)
Converting chemical energy in a spontaneous reaction into electrical energy.
Types of electrochemical cells
1) Electrolytic cell (E) -> Cathode - negative electrode, anode - positive electrode
2) Voltaic cell (V) -> Cathode - positive electrode, anode - negative electrode
Cathode is drawn on the right, anode on the left.
Electrolyte (V)
Each electrolyte is composed of inert electrolytes that allow the transfer of ions between solutions but doesn’t react with the solutions.
Typical electrolytes are sodium sulfate (Na₂SO₄) and potassium chloride (KCl)
Anode (V)
ANO - anode, negative, oxidation
Will be the metal higher in the activity series, the metal will decrease in size as ions are oxidised to aqueous form.
Cathode (V)
CPR - cathode, positive, reduction
Will be the metal lower in the activity series, the metal will grow in size as ions are reduced to solids.
Salt bridge (V)
Allows ions to travel between solutions
Wires (V)
Transfer electrons from anode to cathode
Daniell voltaic cell
Made of zinc and copper electrodes. Zinc is the anode and copper is the cathode.
Cu²⁺ + Zn -> Cu + Zn²⁺
