galvanic and electrolytic cell exp 1 cmt555.docx

Materials, Engineering, Applications, 2010

Introduction: Chemical reactions involving the transfer of electrons from one reactant to another are called oxidation-reduction reactions or redox reactions. In a redox reaction, two half-reactions occur; one reactant gives up electrons (undergoes oxidation) and another reactant gains electrons (undergoes reduction). A piece of zinc going into a solution as zinc ions, with each Zn atom giving up 2 electrons, is an example of an oxidation half-reaction.

muduku ivan

Is the potential difference between an element and an aqueous solution of its ions, when it is in equilibrium with its ions. Consider a metal dipped into a solution of its ions, e.g. a Zinc rod dipped in a solution of zinc ions such as zinc sulphate. Two processes may occur;  Metal atoms may ionize leaving a buildup of electrons on the metal surface, metal becomes negatively charged. Zn(s) → Zn 2+ (aq) + 2e  Metal ions from a solution may take up electrons from the rod of the metal; discharged as metal atoms; metal becomes positively charged. Zn 2+ (aq) + 2e → Zn(s) Because of different rates at which the above process occur, and the high electro positivity of the zinc metal, tendency to ionize outweigh the tendency to gain electrons; electrons accumulate on its surface, becomes more negative with respect to the solution.

2020

The field of electrochemistry can be defined as the set of physical and chemical phenomena involved by the passage of an electric current in an ionic conductor. These phenomena involve the use of electrodes characterized by at least one interface common to two conductors of different nature. They manifest themselves in various ways in electrochemical reactors made up of two electronic conductors or electrodes separated by an ionic conductive medium. After having defined the main phenomena involved in the flow of current, the article presents the thermodynamic and kinetic aspects of electrochemistry (electrochemical cell). The main industrial applications of electrochemistry are briefly presented.

Journal of Chemical Education, 1996