Electrochemistry

E10

Electrochemistry and Thermodynamics

E10 Electrochemistry and Thermodynamics

INTRODUCTION

In this experiment you will study the electrochemistry of voltaic (galvanic) cells and in the process determine the values of the thermodynamic functions ∆G, ∆H, and ∆S. You will construct electrochemical cells by combining different metallic systems and their solutions. Measuring the potential of the prepared cells at various temperatures will render the values of the thermodynamic functions ∆G, ∆H, and ∆S corresponding to the electrochemical system studied.

THEORETICAL BACKGROUND

Electrochemistry:

Electrochemistry is the area of chemistry that deals with the relation between chemical changes and electrical energy. Chemical reactions can be used to produce electrical energy in voltaic (galvanic) cells. Electrical energy, on the other hand can be used to bring about chemical changes in what are termed electrolytic cells. In this experiment you will investigate some of the properties of voltaic cells.

Oxidation- reduction reactions are those that involve the transfer of electrons from one substance to another. A redox reaction is the simultaneous occurrence of the two components or half reactions. Oxidation occurs when a chemical species loses or gives up electrons to another chemical species. Reduction occurs when a chemical species receives or gain electrons. The oxidation process provides the electrons necessary for reduction to occur. Therefore, the oxidized species is the reducing agent., and the reduced species is the oxidizing agent.

For example, if a piece of zinc metal is immersed into a solution containing copper (II) ions, zinc will be oxidized by the copper (II) ions. Zinc loses electrons and it is oxidized while copper (II) ions gain electrons and are reduced. We can conveniently express these two processes by the following two half-reactions, which add to give the overall redox reaction.

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The function of a...