Zinc copper electrochemical battery

In many secondary school textbooks, the topic of electrochemical cells is introduced after redox reactions by demonstrating a galvanic cell, very often the Daniell cell (zinc-copper cell). But for students, this experiment is overwhelming because of this cell does not look like a battery. Moreover, the experiment is confusing for students because of the large number of new phenomena and the complexity of the explanations. We would propose to start with a more simple experiment that clarifies some basic characteristics of cells, especially the concepts of electrolyte, electrode and electrode reaction. 

Environmental hazards of batteries can be briefly summarized as follows. A battery is an electrochemical device with the ability to convert chemical energy to electrical energy to provide power to electronic devices. Batteries may contain lead, cadmium, mercury, copper, zinc, lead, manganese, nickel, and lithium, which can be hazardous when incorrectly disposed. Batteries may produce the following potential problems or hazards (a) they pollute the lakes and streams as the metals... 

In these redox reactions, there is a simultaneous loss and gain of electrons. In the oxidation reaction part of the reaction (oxidation half-reaction), electrons are being lost, but in the reduction half-reaction, those very same electrons are being gained. Therefore, in redox reactions there is an exchange of electrons, as reactants become products. This electron exchange may be direct, as when copper metal plates out on a piece of zinc or it may be indirect, as in an electrochemical cell (battery). 

The actual cell voltage is about 1.5 V, it does not depend on the actual pH-value of the electrolyte solution as obvious from the absence of protons and hydroxide ions in the cell reaction equation. It slightly depends on the source of the used manganese dioxide. Initially naturally occurring manganese dioxide was used. The battery required a quality of less than 0.5% copper, nickel, cobalt, and arsenic to avoid undue corrosion of the zinc electrode. Currently synthetic manganese dioxide is prepared either by chemical (CMD) or electrochemical (EMD) procedures. For improved electrical conductivity graphite or acetylene black are added. Upon deep... 

VASP is also able to simulate the Daniell battery [106]. The model is a bimetallic slab consisting of two parts in epitaxy, one made of copper and the other of zinc. The interspace between the successive slabs is filled by four layers of water, originally in a hexagonal ice arrangement, and the optimization is run. One layer of water decomposes, the OH being adsorbed on Cu and the ff" on the Zn. There is a relaxation of the metal surfaces at the interfaces, some Zn atoms moving significantly outward. A limited periodic model accounts then for a typical electrochemical reaction. 

Redox Reactions. For many electrochemists the paramount concern of their discipline is the reduction and oxidation (redox) reaction that occurs in electrochemical cells, batteries, and many other devices and applications. Reduction takes place when an element or radical (an ionic group) gains electrons, such as when a double positive copper ion in solution gains two electrons to form metallic copper. Oxidation takes place when an element or radical loses electrons, such as when a zinc electrode loses two electrons to form a doubly positive zinc ion in solution. In electrochemical research and applications the sites of oxidation and reduction are spatially separated. The electrons produced by chemical processes can be forced to flow through a wire, and this... 

John Frederic Daniell (1790-1845) was an English scientist who is well known for his invention of the Daniell cell, which is one of the earliest prototypes of electric batteries. The Daniell cell consists of two metal, copper and zinc, electrodes and is a classical electrochemical system conunonly used in electrochemical education. 

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