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Topic: Galvanic cell


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  Galvanic cell - Wikipedia, the free encyclopedia
The Galvanic cell, named after Luigi Galvani, consists of two metals connected by an electrolyte which forms a salt bridge between the metals.
The Galvanic cell's metals dissolve in the electrolyte at two different rates, leaving some electrons in the rest of the metal, which charges it negative with respect to the electrolyte.
Unwanted galvanic cells are formed whenever two metals are in contact in the presence of an electrolyte, such as salt water, resulting in the galvanic corrosion of the more active metal.
en.wikipedia.org /wiki/Galvanic_cell   (661 words)

  
 Galvanic cell having rechargeable zinc electrode - Patent 4145482
Galvanic cell according to claim 1, in which the zinc electrode is disposed in a pocket closed on at least one side and fashioned as an auxiliary structure.
The galvanic cell of claim 1, in which the capacity of the zinc electrode, with a predetermined zinc concentration in the electrolyte, can be adjusted by the distance of the at least one auxiliary structure from the current discharge structure of the zinc electrode.
The galvanic cell according to claim 1, wherein the openings of the at least one coarse-pored auxiliary structure are of such size that hydrogen formed at the structure is permitted to rapidly escape therethrough.
www.freepatentsonline.com /4145482.html   (2872 words)

  
 Galvanic cell having a primary radial seal and a secondary resealable vent closure - Patent 4112200
In the galvanic cell of claim 1 wherein the resiliently compressible elastomeric sponge gasket is composed of a large number of non-interconnected pores thereby providing a resealable vent closure at the interface of the cover and the rim of the container.
In the galvanic cell of claim 6 wherein the resiliently compressible elastomeric sponge gasket is composed of a large number of non-interconnected pores thereby providing a resealable vent closure at the interface of the cover and the rim of the container.
In the galvanic cell of claim 11 wherein the resiliently compressible elastomeric sponge gasket is composed of a large number of non-interconnected pores thereby providing a resealable vent closure at the interface of the cover and the rim of the container.
www.freepatentsonline.com /4112200.html   (3476 words)

  
 Galvanic cell - US Patent 5436090   (Site not responding. Last check: 2007-11-06)
A cell is obtained with use of a solid electrolyte prepared by dissolving a trifunctional terminal acryloyl-modified alkylene oxide polymer having a polymer chain represented by the following formula (1) and an electrolyte salt in a solvent, and then by crosslinking it by a radioactive ray irradiation and/or by heating.
The galvanic cell according to the present invention is which is produced by using a solid electrolyte prepared by dissolving a trifunctional polymer in a solvent together with an electrolyte salt and crosslinking it by a radioactive ray irradiation and/or by heating.
In the galvanic cell of the present invention, it is preferred that the solid electrolyte composition (or a mixture thereof with an electrode active material) is coated on the surface of the electrode material and crosslinked to form a uniform solid electrolyte layer (or a composite electrode) on the electrode surface.
www.patentstorm.us /patents/5436090.html   (5125 words)

  
 Electrochemical cell - Wikipedia, the free encyclopedia
An electrochemical cell is a setup used for creating an electromotive force in a conductor separating two reactions.
The current is caused by the reactions releasing and accepting electrons in to the different ends of the conductor.
In a full electrochemical cell, one side must be losing electrons (oxidation) in to its electrode while the other half-cell gains electrons (reduction).
en.wikipedia.org /wiki/Electrochemical_cell   (314 words)

  
 Galvanic cell -- Facts, Info, and Encyclopedia article   (Site not responding. Last check: 2007-11-06)
It is also known as a (An electric cell that generates an electromotive force by an irreversible conversion of chemical to electrical energy; cannot be recharged) voltaic cell and an (Click link for more info and facts about electrochemical cell) electrochemical cell.
The Galvanic cell's metals dissolve in the (A solution that conducts electricity) electrolyte at a different rate, leaving some electrons in the rest of the metal, which charges it.
Unwanted galvanic cells are formed whenever two metals are in contact in the presence of an (A solution that conducts electricity) electrolyte, such as salt water, resulting in the galvanic (Erosion by chemical action) corrosion of the more active metal.
www.absoluteastronomy.com /encyclopedia/g/ga/galvanic_cell.htm   (787 words)

  
 Electrochemistry
Galvanic cells harness the electrical energy available from the electron transfer in a redox reaction to perform useful electrical work.
A cell consists of two dissimilar substances, a positive electrode and a negative electrode, that conduct electricity, and a third substance, an electrolyte, that acts chemically on the electrodes.
In the process of charging, the cell is made to operate in reverse of its discharging operation; i.e., current is forced through the cell in the opposite direction, causing the reverse of the chemical reaction that ordinarily takes place during discharge, so that electrical energy is converted into stored chemical energy.
www.angelfire.com /geek/kneekey/topic11.htm   (1485 words)

  
 Hermetically sealed galvanic cell - Patent 4774155
The galvanic cell of claim 5 wherein the adhesive is selected from the group consisting of fatty acid polyamides, polyisobutylene pressure-sensitive masses, cold-curing cyanoacrylates and melt-adhesives based on polyamides.
The galvanic cell of claim 1 wherein the coating is comprised of an alkali-resistant lacquer.
The present invention pertains to a galvanic cell having a negative zinc electrode, an alkaline electrolyte, and a housing which is sealed by a sealing member made of plastic and having a predetermined breaking point in the form of a bursting membrane or a score.
www.freepatentsonline.com /4774155.html   (1317 words)

  
 Exam4A_Sp97
In both a galvanic cell and an electrolytic cell, electrons flow externally to the cell and ions flow internally in the cell.
In a galvanic cell the anode is assigned the negative electrode, but in an electrolytic cell the anode is assigned the positive electrode.
Galvanized steel is more resistant to corrosion than unprotected steel because the zinc coating has a lower reduction potential than does the iron of the steel.
www.tamuk.edu /chemistry/kfjb000/1312Ex4S97.htm   (647 words)

  
 New Technology Batteries Guide: Fundamentals of Battery Technology   (Site not responding. Last check: 2007-11-06)
A galvanic cell is a fairly simple device consisting of two electrodes (an anode and a cathode) and an electrolyte solution.
Cells with irreversible reactions are commonly known as primary cells, while cells with reversible reactions are known as secondary cells.
The amount of voltage and current that a galvanic cell produces is directly related to the types of materials used in the electrodes and electrolyte.
www.nlectc.org /txtfiles/batteryguide/ba-fund.htm   (1040 words)

  
 Galvanic corrosion   (Site not responding. Last check: 2007-11-06)
Galvanic corrosion can be one of the most common forms of corrosion as well as one of the most destructive.
Galvanic corrosion problems should be solved by designing to avoid these problems in the first place.
Galvanic corrosion cells can be set up on the macroscopic level or on the microscopic level.
www.corrosion-doctors.org /Aircraft/galvdefi.htm   (550 words)

  
 SCH4U Electrochemistry: Cell Reactions   (Site not responding. Last check: 2007-11-06)
A galvanic cell is also referred to as a voltaic cell or Daniell cell.
The common household battery is an example of a galvanic cell.
If the salt bridge is not there, the cell that is performing the reduction would become very negative, because the negative anion must remain while all the positive cations are being reduced.
www.ucdsb.on.ca /tiss/stretton/chem2/electro6.htm   (751 words)

  
 SparkNotes: Electrolytic Cells: Electrolysis
The concept of reversing the direction of the spontaneous reaction in a galvanic cell through the input of electricity is at the heart of the idea of electrolysis.
Though the direction of electron flow in electrolytic cells may be reversed from the direction of spontaneous electron flow in galvanic cells, the definition of both cathode and anode remain the same--reduction takes place at the cathode and oxidation occurs at the anode.
Note that copper is spontaneously plated onto the copper cathode in the galvanic cell whereas it requires a voltage greater than 0.78 V from the battery to plate iron on its cathode in the electrolytic cell.
www.sparknotes.com /chemistry/electrochemistry/electrolytic/section1.html   (1027 words)

  
 Silver Equilibria
The classical galvanic cell serves well as a teaching device and in a few instances the measurement of potential is quite reliable as a means for determining metal ligand equilibrium constants.
The cell potential of a galvanic cell involving aqueous solutions varies with the concentrations of the solutes involved in the reaction.
Q is the thermodynamic reaction quotient for the cell reaction and n is the number of electrons transferred in the balanced cell reaction.
www.chem.queensu.ca /PROGRAMS/UG/Firstyearlabs/112&116/labman/manual/lab11   (1018 words)

  
 Letters - Conceptual understanding of electricity: Galvanic cells
We are aware of the fact that if a metal wire replaces the salt bridge in a galvanic cell the ammeter connected through the circuit may show a reading, but we also know that this current reading is very low (as also stated by Goodwin) compared to the current measured using a salt bridge.
In his Figure 2A, the values of +0.34V and -0.76V are assigned to the external parts of the cathode and anode respectively in the absence of current flow; when the cell potential changes from 1.1V to 0.8V as a result of the moderate current flow, these values are given as +0.24V and -0.56 V respectively.
When current flow is allowed to pass through the cell, i.e., a low impedance pathway is provided until the cell voltage as read on the voltmeter decreases to a particular value, the concentrations of the electro-active species in the anode and cathode compartments also change since chemical changes occur at each half-cell (at each interface).
www.rsc.org /Education/CERP/issues/2004_1/letter1.asp   (2626 words)

  
 NSW HSC ONLINE - Chemistry
A galvanic cell is a device constructed so that a reductant and oxidant are physically separated, but connected by an external circuit made of a conductor (to carry electrons) and a salt bridge (to carry charged ions in solution).
A galvanic cell is thus composed of two half-cells, a reductant half-cell and an oxidant half-cell.
In the galvanic cell example, this is the surface of the copper electrode where electrons are available for the following reaction to occur (resulting in a coating of copper).
hsc.csu.edu.au /chemistry/core/identification/chem924/924net.html   (1967 words)

  
 SparkNotes: Galvanic Cells: Terms and Formulae
Galvanic Cell - An electrochemical cell with a positive cell potential that allows chemical energy to be converted into electrical energy.
The rules for determining the oxidation number of a species are discussed in Galvanic Cells, Oxidation State.
The voltage given by the construction of a galvanic cell between the SHE and the reduction of interest gives the standard reduction potential of that reduction.
www.sparknotes.com /chemistry/electrochemistry/galvanic/terms.html   (804 words)

  
 The Chemistry of Batteries   (Site not responding. Last check: 2007-11-06)
A galvanic cell is defined as "a device in which chemical energy is changed to electrical energy." Galvanic cells, also known as voltaic cells, use spontaneous oxidation and reduction reactions to create an electric current which can be used to perform work.
The charge of a galvanic cell, q, is related to the number of electrons, n, transferred in the redox reactions occurring in the cell.
They function similarly to galvanic cells in that they have an anode and a cathode, however, in fuel cells, hydrogen gas is fed into the anode where it is converted into protons and electrons.
www.uvm.edu /~swgordon/131-01/131web/sarasmoller/finalproject.html   (2298 words)

  
 AP Chem
Galvanic cell  – a device in which chemical energy is changed to electrical energy.
Because the cell potential is sensitive to the concentrations of the reactants and products involved in the cell reaction, measured potentials can be used to determine the concentration of an ion.
Battery – a galvanic cell, or group of galvanic cells connected in series, where the potentials of the individual cells add to give the total battery potential.
www.anderson1.k12.sc.us /schools/pmhs/dept/ap17.htm   (1692 words)

  
 Fuel cell based & galvanic electrochemical sensors: Crowcon Detection Instruments: Gas Facts
Fuel cells are electric batteries, which consume gas from outside rather than solid/liquid materials inside them.
Crowcon fuel cell sensors are miniaturised fuel cells which react to low (parts per million) concentrations of gas.
Galvanic sensors are not fuel cells because electrodes or electrolyte are used up.
www.crowcon.com /talking-gas/talking_gas_electrochemical_systems.htm   (774 words)

  
 New Cartridge-type D.O. Sensor Saves Time, Money
In a basic galvanic cell, the oxygen content of the electrolyte is brought into equilibrium with the sample oxygen content.
Since the output of a galvanic cell is linearly proportional to the amount of oxygen present, the potential for errors at low oxygen levels increases due to a low signal-to-noise ratio.
As long as this voltage is maintained at a constant level, the cell will not be as susceptible to contamination of the electrodes and electrolyte as a galvanic cell.
www.wqpmag.com /wqp/index.cfm/powergrid/rfah=|cfap=/CFID/625177/CFTOKEN/47888385/fuseaction/showArticle/articleID/2340   (808 words)

  
 Outcomes Review Chapter 10   (Site not responding. Last check: 2007-11-06)
In galvanic cells oxidation and reduction half reactions are spatially separated and the free energy of a chemical reaction drives electrons through an external circuit where they can be used to do work.
use the known cell reaction to identify the anode and cathode of an electrochemical cell [Sections 10.1, 10.2, 10.3, and 10.4].
use the known sign for a galvanic cell potential to identify the direction of the cell reaction and the anode and cathode of the cell [Section 10.3].
www.acs.org /portal/a/c/s/1/acsdisplay.html?DOC=\education\curriculum\genchem_chapt10.html   (639 words)

  
 Galvanic Cells and Electrode Potential
The complete cell voltage (the only voltage that can be measured) is the difference between the two reduction potentials.
The anode is also the negative terminal in a galvanic cell.
The anode is to be connected to the negative wire (fl) from the voltmeter.
www.sonoma.edu /users/b/brooks/115b/galvanic.html   (774 words)

  
 Ch110_Lec 13_24 Sept
Galvanic cells (or Voltaic cells) are cells in which the overall redox reactions occur spontaneously (equilibrium favors products) as written.
In each cell the reaction, by convention, is written as a half-reaction, which is in fact the chemistry taking place in the half cells.
Note that in tables of Reduction Potentials the reactions are written as reduction half reactions, with the potentials those which would occur if the half-cell were connected into a galvanic cell with a SHE.
www.humboldt.edu /~rap1/C110.F03/C110Notes/C110_lec13.htm   (834 words)

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