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Topic: Standard electrode potential


  
 NationMaster - Encyclopedia: Electrode potential   (Site not responding. Last check: 2007-10-07)
The electrode potential depends upon the concentrations of the substances, the temperature, and the pressure in the case of a gas electrode.
The standard electrode potentials are customarily determined at solute concentrations of 1 Molar, gas pressures of 1 atmosphere, and a standard temperature which is usually 25°C. The standard cell potential is denoted by a degree sign as a superscript.
The concept of the Donnan potential is analogous to that of the equilibrium electrode potential.
www.nationmaster.com /encyclopedia/Electrode-potential   (863 words)

  
  Electrode potential - Wikipedia, the free encyclopedia
In electrochemistry, electrode potential (also called reversible potential difference or reversible potential difference of an electrode, and abbreviated E) is the potential difference of a half-reaction which occurs across a reversible cell made up of any electrode and a standard hydrogen electrode.
The potential of the cell as a whole is simply the combination of the two electrode potentials relative to a standard hydrogen electrode.
Once the standard electrode potentials of two substances are known, it is possible to predict the direction electrons will travel from one substance to another, as well as the potential measured between them.
en.wikipedia.org /wiki/Electrode_potential   (409 words)

  
 Kids.Net.Au - Encyclopedia > Electrode potential   (Site not responding. Last check: 2007-10-07)
The electrode potential of two ionic half-reactions is the potential difference measured on their connection in an electrochemical cell.
The standard electrode potential of a half-reaction is the potential measured between it and hydrogen in an electrochemical cell at 298K, 1 mol concentration and 1 atm pressure.
Once the standard electrode potentials of two substances are known, it is possible to predict the direction electrons will travel from one substance to another, as well as the the potential measured between them.
www.kids.net.au /encyclopedia-wiki/el/Electrode_potential   (388 words)

  
 Standard electrode potential (data page) - Encyclopedia, History, Geography and Biography
The standard electrode potentials are used to determine the electrochemical potential or the electrode potential of an electrochemical cell or Galvanic cell.
These electrode potentials are experimentally measured with the standard hydrogen electrode, because the true potentials are difficult to measure without error.
Whatever it's actual potential, the hydrogen half reaction is defined to be zero, and thus all the other values are determined by comparison with the potential of the standard hydrogen electrode.
www.arikah.com /encyclopedia/Table_of_standard_electrode_potentials   (212 words)

  
 NationMaster - Encyclopedia: Standard electrode potential   (Site not responding. Last check: 2007-10-07)
Electricity is generated due to electric potential created as a result of difference between individual potentials of the two metal electrodes at the cathode and at the anode terminals.
Since the oxidation potential of a half-reaction is the negative of the reduction potential in a redox reaction, it is sufficient to calculate either one of the potentials.
Given the standard potential of the cell, the non-standard cell potential can be calculated using the Nernst equation: In electrochemistry, the Nernst equation gives the electrode potential (E), relative to the standard electrode potential, (E0), of the electrode couple or, equivalently, of the half cells of a battery.
www.nationmaster.com /encyclopedia/Standard-electrode-potential   (1605 words)

  
 Standard Electrode Potentials
This potential is a measure of the energy per unit charge which is available from the oxidation/reduction reactions to drive the reaction.
It is the nature of electric potential that the zero of potential is arbitrary; it is the difference in potential which has practical consequence.
The second hurdle is overcome by choosing standard thermodynamic conditions for the measurement of the potentials.
hyperphysics.phy-astr.gsu.edu /hbase/chemical/electrode.html   (1055 words)

  
 ELECTRODE POTENTIAL-STANDARD ELECTRODE POTENTIAL-HYDROGEN ELECTRODE
When a metal (electrode) is immersed in a solution containing the ions of that metal, a potential difference is set up between the metal and its ions in the solution.
Electrode potential may be positive or negative depending upon the nature of electrode.
The electrode potential of hydrogen electrode is assumed to be 0.00V at all temperatures.".
www.citycollegiate.com /electrode_potential01.htm   (278 words)

  
 Subcutaneous glucose electrode - Patent 5593852
The recess 6 in the insulated electrode extends from the tip 16 of the electrode which is open to the surrounding environment, to the top 18 of the wire 2 in the insulating sheath, generally for a length c of less than about 0.150 mm, and preferably about 0.125 mm.
At operating potentials of approximately -0.10 to +0.25 for the glucose biosensor, the rate of electrooxidation of interferants such as ascorbate, urate and acetaminophen is very slow relative to that of glucose through its physiological concentration range.
All of the points, from both electrodes, were in regions A and B, with 43 of the 48 points being in region A. The three points in region B near 100 mg/dl glucose, for the electrode implanted between the scapulae, were the last three points of the experiment, at about 410 min.
www.freepatentsonline.com /5593852.html   (8498 words)

  
 Standard hydrogen electrode - Wikipedia, the free encyclopedia
A standard hydrogen electrode (abbreviated SHE) is a redox electrode which is placed in the basis of the thermodynamic scale of oxidation-reduction potentials.
Potentials of any other electrodes are compared with the standard hydrogen electrode.
Because of the high adsorption activity of the platinized platinum electrode, it's very important to protect electrode surface and solution for the presence of organic substances as well as oxygen of atmosphere.
en.wikipedia.org /wiki/Standard_hydrogen_electrode   (195 words)

  
 IB Chemistry notes: electrode potentials
The electrode potential measures the tendency of electrons to flow away from or towards a redox equilibrium.
The value of the electrode potential is a relative value for the equilibrium compared with the standard hydrogen electrode.
The measured potential (using a high resistance voltmeter) is called the cell potential - it is equal to the DIFFERENCE between the electrode potentials of the two half cells.
www.ibchem.com /IB/ibnotes/full/red_htm/19.2.htm   (1903 words)

  
 ANALYTICAL CHEMISTRY - ELEMENTS OF ELECTOCHEMISTRY   (Site not responding. Last check: 2007-10-07)
The potential difference (voltage) between the anode and cathode is a measure of the tendency of the reaction to proceed from nonequilibrium to equilibrium.
The SHE (standard hydrogen electrode) is the reference point for determining relative electrode potentials.
By definition, the electrode potential is the potential of a cell with the standard hydrogen electrode acting as the anode and the other half-cell acting as the cathode.
www.sbuniv.edu /~ggray/CHE3345/chp16.html   (1360 words)

  
 Standard reference electrodes
Standard potential differences are the actual cell potential differences measured in reversible cells under standard conditions.
Tables of standard electrode potentials can be obtained if any one electrode, operated under standard conditions, is designated as the standard electrode or standard reference electrode with which all other electrodes will be compared.
In many practical potential measurements, the standard hydrogen electrode cannot be used because hydrogen reacts with other substances in the cell or because other substances in the cell react with the catalytic platinum electrode surface upon which the H
www.corrosion-doctors.org /References/Standard.htm   (260 words)

  
 UNIT 8* - ADDITIONAL MATERIALS IN REDOX AND ELECTROCHEMISTRY   (Site not responding. Last check: 2007-10-07)
Standard electrode potentials are useful in determining whether or not a specific redox reaction will take place.
Therefore, to obtain the equation and the potential for this oxidation half-reaction, the equation for magnesium as written in the table must be reversed and the sign of E° changed.
NOTE: The Standard Electrode Potentials (E°) are not multiplied by the coefficients in calculating the E° for the reaction.
dwb.unl.edu /Chemistry/LearningObjectives/NY08x.html   (875 words)

  
 OMEGA ENGINEERING -Ion Selective Electrodes
Typically, the ISE (Ion Selective Electrode) that is purchased will come with its own instruction manual that pertains to that particular type of electrode.
(The pH electrode is an ISE for the Hydrogen ion.) This potential is measured against a stable reference electrode of constant potential.
This occurrence will not only alter the potential due to the specific ion that is measured, it may also allow other ions in solution to become active that otherwise were not.
www.omega.com /techref/ph-5.html   (701 words)

  
 Spartanburg SC | GoUpstate.com | Spartanburg Herald-Journal
, is the measure of individual potential of any electrode at standard ambient conditions, which is at a temperature of 298K, solutes at a concentration of 1 M, and gases at a pressure of 1 bar.
This potential difference is created as a result of the difference between individual potentials of the two metal electrodes with respect to the electrolyte.
To overcome the difficulty of measuring individual potential of an electrode, an electrode of unknown reduction potential at anode can be paired with a standard cathode whose unknown potential has been defined to be zero.
www.goupstate.com /apps/pbcs.dll/section?category=NEWS&template=wiki&text=electrode_potential   (743 words)

  
 S - Glossary of chemical terms
Standard temperature (273.15 K) and pressure (101 325 Pa) is the standard conditions used as a basis for calculations involving quantities that vary with temperature and pressure.
Standard electrode potential (E°) (standard reduction potentialis) are defined by measuring the potential relative to a standard hydrogen electrode using 1 mol solution at 25 °C. The convention is to designate the cell so that the oxidized form is written first.
Standard hydrogen electrode is a system in which hydrogen ion and gaseous hydrogen are present in their standard states.
www.ktf-split.hr /periodni/en/abc/s.html   (1490 words)

  
 Silver halide light-sensitive material comprising polymerizable layer provided on aluminum support - Patent 5393651
The standard electrode potential means an equilibrium electrode potential where all the electrode reaction components of a simple electrode are present at standard conditions.
According to the present invention, the standard electrode potential is measured at 25.degree.
The metal cation or the metal oxide anion having a standard electrode potential of 0 V or more means an oxidizing ion showing a standard electrode potential of 0 V or more against a reducing ion, metal or compound.
www.freepatentsonline.com /5393651.html   (10855 words)

  
 Reference.com/Encyclopedia/Electrochemical gradient
This can be calculated as a thermodynamic measure termed electrochemical potential that combines the concepts of energy stored in the form of chemical potential which accounts for an ion's concentration gradient across a cellular membrane and electrostatics which accounts for an ion's tendency to move relative to the membrane potential.
Membrane transport proteins such as the sodium-potassium pump within the membrane are equivalent to turbines that convert the waters potential energy to other forms of physical or chemical energy, and the ions that pass through the membrane are equivalent to water that is now found at the bottom of the dam.
The electrochemical potential difference between the two sides of the membrane in mitochondria, chloroplasts, bacteria and other membranous compartments that engage in active transport involving proton pumps, is at times called a chemiosmotic potential or proton motive force (see chemiosmotic hypothesis).
www.reference.com /browse/wiki/Chemiosmotic_potential   (1062 words)

  
 Electrochemistry
The zinc is observed to be at a voltage of -0.761V with respect to the hydrogen electrode.
The oxidation potential is the negative of the reduction potential, 0.761 V in this case.
The electrode potentials that are shown in tables are, unless otherwise specified, the standard electrode potentials, since they refer to specific concentrations of the reactants and a specific temperature.
www.du.edu /%7Ejcalvert/phys/elechem.htm   (6270 words)

  
 Redox Potentiometry
The standard electrode is a hydrogen half-cell, with the reaction
Equation 2 is the simplest form of the equation defining the relation between redox potential (electrode potential) and the concentrations of the redox couple (or the half-cell reactants).
Measure the electrode potential of the half-cell as the concentration ratio of oxidized and reduced components is varied.
www.life.uiuc.edu /crofts/bioph354/redox.html   (1417 words)

  
 Standard hydrogen electrode (SHE)   (Site not responding. Last check: 2007-10-07)
It is a type of gas electrode and was widely used in early studies as a reference electrode, and as an indicator electrode for the determination of pH values.
The platinum electrode is made of a small square of platinum foil which is platinized (known as platinum fl).
It is interesting to note that even though the SHE is the universal reference standard, it exists only as a theoretical electrode which scientists use as the definition of an arbitrary reference electrode with a half-cell potential of 0.00 volts.
www.corrosion-doctors.org /References/hydrogen.htm   (335 words)

  
 Table of standard electrode potentials
These electrode potentials are experimentally calculated, because one cannot determine the voltage from the chemical equations.
The hydrogen half reaction was chosen to be zero, and thus all the other values were determined by their voltage with the hydrogen half reaction.
The values below are standard electrode potentials taken at 298K, 1atm pressure and in aqueous solution, of concentration 1 molar.
www.ufaqs.com /wiki/en/ta/Table%20of%20standard%20electrode%20potentials.htm   (138 words)

  
 Electrode potential -- Facts, Info, and Encyclopedia article   (Site not responding. Last check: 2007-10-07)
It is clear, then, that both half-reactions contribute to the potential measured.
In order to isolate the potentials of individual half-reactions, measurements against hydrogen as the second half-cell are made:
In this case a positive potential indicates that the (A stable situation in which forces cancel one another) equilibrium of the Fe /Fe reaction lies towards Fe, meaning that it accepts electrons from the hydrogen half-reaction.
www.absoluteastronomy.com /encyclopedia/E/El/Electrode_potential.htm   (369 words)

  
 ChemCases: Cisplatin - 4. Electrochemistry
Standard electrode potentials are all measured in reference to the hydrogen electrode’s standard potential, which is arbitrarily set at zero.
We will see that the cell potential is related both to the reaction free energy, which tells us whether or not the reaction is spontaneous, and to the equilibrium constant for the reaction, which tells us the extent of the reaction at equilibrium.
We see that the net potential for the redox reaction occurring in the potassium iodide-starch test is a positive number; this will lead to a negative value for the reaction free energy, meaning that the reaction is spontaneous as written.
chemcases.com /cisplat/cisplat04.htm   (1307 words)

  
 an introduction to redox equilibria and electrode potentials
The emf measured when a metal / metal ion electrode is coupled to a hydrogen electrode under standard conditions is known as the standard electrode potential of that metal / metal ion combination.
By convention, the hydrogen electrode is always written as the left-hand electrode of the cell.
Remember that the standard electrode potential of a metal / metal ion combination is the emf measured when that metal / metal ion electrode is coupled to a hydrogen electrode under standard conditions.
www.chemguide.co.uk /physical/redoxeqia/introduction.html   (2410 words)

  
 Applications of Standard Electrode Potentials
The strengths of oxidizing and reducing agents are indicated by their standard electrode potentials.
A sample from the table of standard potentials shows the extremes of the table.
The cell potential of a voltaic cell is a measure of the maximum amount of energy per unit charge which is available to do work when charge is transferred through an external circuit.
hyperphysics.phy-astr.gsu.edu /hbase/chemical/electrode2.html   (433 words)

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