Final answer:
Electrochemical cells are devices converting chemical to electrical energy using redox reactions. Thermodynamics, especially Gibbs free energy, helps predict the spontaneity and efficiency of these reactions. Galvanic cells use spontaneous reactions to create electricity, while electrolytic cells use electricity to drive non-spontaneous reactions.
Step-by-step explanation:
Electrochemical Cells
Electrochemical cells are devices that convert chemical energy into electrical energy or vice versa through redox reactions. They consist of two electrodes connected by an electrolyte and a wire circuit. The electrons flow through the wire from the anode to the cathode, creating an electric current.
Thermodynamic Principles
In thermodynamics, free energy, specifically Gibbs free energy (G), is used to predict the spontaneity of a process. A negative value for Gibbs free energy change indicates a spontaneous reaction, which is the case for galvanic cells. These principles help in quantifying the maximum work a system can perform and its efficiency.
Faraday's Law
Faraday's Law of electrolysis states that the amount of substance that undergoes oxidation or reduction at each electrode during electrolysis is directly proportional to the amount of electric charge passed through the cell. This relationship is fundamental for performing stoichiometric calculations for electrolytic processes.
Galvanic Cells
Galvanic cells, also known as voltaic cells, generate electricity from spontaneous chemical reactions, such as the zinc and copper(II) sulfate reaction (Zn(s) + Cu²+ (aq) → Zn²+ (aq) + Cu(s)). In this type of cell, the energy released by the redox reaction is harnessed as electrical energy.
Electrolytic vs. Galvanic Cells
The operation of electrolytic cells differs from that of galvanic cells because they use electrical energy to drive a non-spontaneous chemical reaction, while galvanic cells use the energy of a spontaneous chemical reaction to generate electrical energy. Elements like aluminum, chlorine, and hydrogen can be produced by electrolysis.