Electrochemical Cells

Topic Content:

In the diagram below zinc is in contact with zinc ions, and metallic copper with copper(II) ions.

An electric current will be generated by the flow of electrons through the wire which connects the two metal solutions. The flow is due to the differences between the two electrodeElectrodes are conductors, in the form of wires, rods or plates, through which current enters and leaves the electrolyte. When the current leaves the electrodes it is known as the cathode... More potentials.

Chemical energyEnergy is the ability to do work. Energy exists in several forms such as heat, kinetic or mechanical energy, light, potential energy, and electrical energy. Units of Energy: The SI unit... More (from the reaction between metal and its solution) is converted into electrical energy.

Electrochemical Cell:

An electrochemical cell is a device in which chemical energy is converted into electrical energy. It is also known as voltaic cell or galvanic cell.

The electrochemical cell consists of two half-cells:

1. An Oxidation half-cell reaction occurs at the electrode in one half-cell.

2. A complementary reduction half-cell reaction occurs at the electrode in the other half-cell.

The reaction is a redox reaction.

At the Zinc electrode (anodeAn anode is an electrode of a polarized electrical device through which conventional current enters the device. It is the positive part of electrolytes where oxidation takes place. More):

Zinc loses two electrons to become zinc ions

 Zn_(s)  →  Zn²⁺ _(aq)   + 2e^– (Oxidation) 

The excess electron at the zinc electrode flows along the wire to the copper electrode where they are taken up by Cu²⁺

At the copper Electrode (cathodeA cathode is the electrode from which a conventional current leaves the electrolyte. It is the negative part of the cell where reduction takes place. More)

Cu²⁺ ions gain two electrons to