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The electrochemical series, which consists of standard electrode potentials and is closely related to the reactivity series, was generated by measuring the difference in potential between the metal half-cell in a circuit with a standard hydrogen half-cell, connected by a salt bridge. The standard hydrogen half-cell: 2H + (aq) + 2e − → H 2 (g)
A demonstration electrochemical cell setup resembling the Daniell cell. The two half-cells are linked by a salt bridge carrying ions between them. Electrons flow in the external circuit. An electrochemical cell is a device that generates electrical energy from chemical reactions.
Often, the concept of half reactions is used to describe what occurs in an electrochemical cell, such as a Galvanic cell battery. Half reactions can be written to describe both the metal undergoing oxidation (known as the anode) and the metal undergoing reduction (known as the cathode). Half reactions are often used as a method of balancing ...
In electrochemistry, cell notation or cell representation is a shorthand method of expressing a reaction in an electrochemical cell.. In cell notation, the two half-cells are described by writing the formula of each individual chemical species involved in the redox reaction across the cell, with all other common ions and inert substances being ignored.
A concentration cell is an electrochemical cell where the two electrodes are the same material, the electrolytes on the two half-cells involve the same ions, but the electrolyte concentration differs between the two half-cells. An example is an electrochemical cell, where two copper electrodes are submerged in two copper(II) sulfate solutions ...
A galvanic cell consists of two half-cells, such that the electrode of one half-cell is composed of metal A, and the electrode of the other half-cell is composed of metal B; the redox reactions for the two separate half-cells are thus: A n + + n e − ⇌ A B m + + m e − ⇌ B. The overall balanced reaction is:
For example, the absolute half-cell entropy has been defined as the entropy of the absolute half-cell process defined above. [4] An alternative definition of the absolute half-cell entropy has recently been published by Fang et al. [5] who define it as the entropy of the following reaction (using the hydrogen electrode as an example):
In electrochemistry, the Nernst equation is a chemical thermodynamical relationship that permits the calculation of the reduction potential of a reaction (half-cell or full cell reaction) from the standard electrode potential, absolute temperature, the number of electrons involved in the redox reaction, and activities (often approximated by concentrations) of the chemical species undergoing ...