Examples of electrode potential in the following topics:
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- To figure this out, it is important to consider the standard electrode potential, which is a measure of the driving force behind a reaction.
- The sign of the standard electrode potential indicates in which direction the reaction must proceed in order to achieve equilibrium.
- What happens to the standard electrode potential when the reaction is written in the reverse direction?
- Neither the relative strengths of the oxidizing or reducing agents nor the magnitude of the potential will change.
- However, what will change is the sign of the standard electrode potential.
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- Electricity is generated due to the electric potential difference between two electrodes.
- In electrochemistry, the standard electrode potential, abbreviated E°, is the measure of the individual potential of a reversible electrode at standard state, which is with solutes at an effective concentration of 1 M, and gases at a pressure of 1 atm.
- Since the standard electrode potentials are given in their ability to be reduced, the bigger the standard reduction potentials, the easier they are to be reduced; in other words, they are simply better oxidizing agents.
- For example, F2 has a potential of 2.87 V and Li+ has a potential of -3.05 V.
- In the example of Zn2+, whose standard reduction potential is -0.76 V, it can be oxidized by any other electrode whose standard reduction potential is greater than -0.76 V and can be reduced by any electrode with standard reduction potential less than -0.76 V.
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- In other systems, the electrode reactions can involve electrode metal as well as electrolyte ions.
- In order to determine which species in solution will be oxidized and which will be reduced, the standard electrode potential of each species may be obtained from a table of standard reduction potentials, a small sampling of which is shown here:
- Historically, oxidation potentials were tabulated and used in calculations, but the current standard is to only record the reduction potential in tables.
- If a problem demands use of oxidation potential, it may be interpreted as the negative of the recorded reduction potential.
- Positive potential is more favorable in this case.
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- The electrode potential for this interconversion may therefore be used to measure the pH of solutions.
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- Reduction potential (also known as redox potential, oxidation/reduction potential, or Eh) measures the tendency of a chemical species to acquire electrons and thereby be reduced.
- Reduction potential is measured in volts (V) or millivolts (mV).
- Each species has its own intrinsic reduction potential.
- The standard reduction potential is defined relative to a standard hydrogen electrode (SHE) reference electrode, which is arbitrarily given a potential of 0.00 volts.
- However, because these can also be referred to as "redox potentials," the terms "reduction potentials" and "oxidation potentials" are preferred by the IUPAC.
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- Each half-cell is associated with a potential difference whose magnitude depends on the nature of the particular electrode reaction and on the concentrations of the dissolved species.
- The sign of this potential difference depends on the direction (oxidation or reduction) in which the electrode reaction proceeds.
- Therefore, the half-cell potential for the Zn/Zn2+ electrode always refers to the reduction reaction:
- For this reason, the potential difference contributed by the left half-cell has the opposite sign to its conventional reduction half-cell potential.
- Predict whether a metal will dissolve in acid, given its reduction potential
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- Recall that standard cell potentials can be calculated from potentials E0cell for both oxidation and reduction reactions.
- A positive cell potential indicates that the reaction proceeds spontaneously in the direction in which the reaction is written.
- Conversely, a reaction with a negative cell potential proceeds spontaneously in the reverse direction.
- One beaker contains 0.15 M Cd(NO3)2 and a Cd metal electrode.
- The other beaker contains 0.20 M AgNO3 and a Ag metal electrode.
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- NiMH batteries use positive electrodes of nickel oxyhydroxide (NiOOH), as does the NiCd, but the negative electrodes use a hydrogen-absorbing alloy instead of cadmium.
- The lithium-ion battery is a family of rechargeable batteries in which lithium ions move from the negative electrode to the positive electrode during discharge, and back when charging.
- The negative electrode of a conventional lithium-ion cell is made from carbon.
- The positive electrode is a metal oxide, and the electrolyte is a lithium salt in an organic solvent.
- The advantages of LiPo over the lithium-ion design include potentially lower cost of manufacture, adaptability to a wide variety of packaging shapes, reliability, and ruggedness.
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- If an evacuated glass tube is equipped with two electrodes and a voltage is applied, the glass opposite the negative electrode is observed to glow from electrons emitted from the cathode.
- The early cold cathode vacuum tubes, called Crookes tubes, used a high electrical potential between the anode and the cathode to ionize the residual gas in the tube.
- The voltage applied between the electrodes accelerates these low mass particles to high velocities.
- In 1838, Michael Faraday passed a current through a rarefied air-filled glass tube and noticed a strange light arc with its beginning at the cathode (negative electrode) and its end almost at the anode (positive electrode).
- Connect the two electrodes to a high voltage source and see them produce cathode rays.
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- Electrochemical cells have two conductive electrodes, called the anode and the cathode.
- The anode is defined as the electrode where oxidation occurs.
- The cathode is the electrode where reduction takes place.
- The metal electrodes are immersed in electrolyte solutions.
- During the reaction, the zinc electrode will be used and the metal will shrink in size, while the copper electrode will become larger due to the deposited Cu that is being produced.