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Absolute Electrode Potential
Absolute electrode potential, in electrochemistry, according to an IUPAC definition, is the electrode potential of a metal measured with respect to a universal reference system (without any additional metal–solution interface). Definition According to a more specific definition presented by Trasatti, the absolute electrode potential is the difference in electronic energy between a point inside the metal (Fermi level) of an electrode and a point outside the electrolyte in which the electrode is submerged (an electron at rest in vacuum just above the electrolyte surface). This potential is difficult to determine accurately. For this reason, a standard hydrogen electrode is typically used for reference potential. The absolute potential of the SHE is 4.44 ± 0.02 V at 25 °C. Therefore, for any electrode at 25 °C: :E^M_ = E^M_+(4.44 \pm 0.02)\ where: : is electrode potential :V is the unit volt :''M'' denotes the electrode made of metal M :(abs) denot ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Electrochemistry
Electrochemistry is the branch of physical chemistry concerned with the relationship between Electric potential, electrical potential difference and identifiable chemical change. These reactions involve Electron, electrons moving via an electronically conducting phase (typically an external electrical circuit, but not necessarily, as in Electroless nickel-phosphorus plating, electroless plating) between electrodes separated by an ionically conducting and electronically insulating electrolyte (or ionic chemical species, species in a Solution (chemistry), solution). When a chemical reaction is driven by an electrical Voltage, potential difference, as in electrolysis, or if a potential difference results from a chemical reaction as in an electric battery or fuel cell, it is called an ''electrochemical'' reaction. Unlike in other chemical reactions, in electrochemical reactions electrons are not transferred directly between atoms, ions, or molecules, but via the aforementioned electron ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Alexander Frumkin
Alexander Naumovich Frumkin (; 24 October 1895 – 27 May 1976) was a Soviet Russian electrochemist, member of the Russian Academy of Sciences since 1932, founder of the Russian Journal of Electrochemistry '' Elektrokhimiya'' and receiver of the Hero of Socialist Labor award. The Russian Academy of Sciences' A.N. Frumkin Institute of Physical Chemistry and Electrochemistry is named after him. Biography Early life Frumkin was born in Kishinev, in the Bessarabia Governorate of the Russian Empire (now Moldova) to a Jewish family; his father was an insurance salesman. His family moved to Odessa, where he received his primary schooling; he continued his education in Strasbourg, and then at the University of Bern. Frumkin's first published articles appeared in 1914, when he was only 19; in 1915, he received his first degree, back in Odessa. Two years later, the seminal article "Electrocapillary Phenomena and Electrode Potentials" was published. Frumkin moved to Moscow in 19 ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Standard Electrode Potential
In electrochemistry, standard electrode potential E^\ominus, or E^\ominus_, is the electrode potential (a measure of the reducing power of any element or compound) which the IUPAC "Gold Book" defines as ''"the value of the standard emf ( electromotive force) of a cell in which molecular hydrogen under standard pressure is oxidized to solvated protons at the left-hand electrode"''. Background The basis for an electrochemical cell, such as the galvanic cell, is always a redox reaction which can be broken down into two half-reactions: oxidation at anode (loss of electron) and reduction at cathode (gain of electron). Electricity is produced due to the difference of electric potential between the individual potentials of the two metal electrodes with respect to the electrolyte. Although the overall potential of a cell can be measured, there is no simple way to accurately measure the electrode/electrolyte potentials in isolation. The electric potential also varies with temperat ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Galvani Potential
In electrochemistry, the Galvani potential (also called Galvani potential difference, or inner potential difference, Δφ, delta phi) is the electric potential difference between two points in the bulk of two phases. These phases can be two different solids (e.g., two metals joined), or a solid and a liquid (e.g., a metal electrode submerged in an electrolyte). The Galvani potential is named after Luigi Galvani. Galvani potential between two metals First, consider the Galvani potential between two metals. When two metals are electrically isolated from each other, an arbitrary voltage difference may exist between them. However, when two different metals are brought into electronic contact, electrons will flow from the metal with a lower voltage to the metal with the higher voltage until the Fermi level of the electrons in the bulk of both phases are equal. The actual numbers of electrons that passes between the two phases is small (it depends on the capacitance between the objects ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Electrochemical Potential
Electrochemistry is the branch of physical chemistry concerned with the relationship between electrical potential difference and identifiable chemical change. These reactions involve electrons moving via an electronically conducting phase (typically an external electrical circuit, but not necessarily, as in electroless plating) between electrodes separated by an ionically conducting and electronically insulating electrolyte (or ionic species in a solution). When a chemical reaction is driven by an electrical potential difference, as in electrolysis, or if a potential difference results from a chemical reaction as in an electric battery or fuel cell, it is called an ''electrochemical'' reaction. Unlike in other chemical reactions, in electrochemical reactions electrons are not transferred directly between atoms, ions, or molecules, but via the aforementioned electronically conducting circuit. This phenomenon is what distinguishes an electrochemical reaction from a conventional ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Vapor Pressure
Vapor pressure or equilibrium vapor pressure is the pressure exerted by a vapor in thermodynamic equilibrium with its condensed phases (solid or liquid) at a given temperature in a closed system. The equilibrium vapor pressure is an indication of a liquid's thermodynamic tendency to evaporate. It relates to the balance of particles escaping from the liquid (or solid) in equilibrium with those in a coexisting vapor phase. A substance with a high vapor pressure at normal temperatures is often referred to as '' volatile''. The pressure exhibited by vapor present above a liquid surface is known as vapor pressure. As the temperature of a liquid increases, the attractive interactions between liquid molecules become less significant in comparison to the entropy of those molecules in the gas phase, increasing the vapor pressure. Thus, liquids with strong intermolecular interactions are likely to have smaller vapor pressures, with the reverse true for weaker interactions. The vapor p ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Point Of Zero Charge
The point of zero charge (pzc) is generally described as the pH at which the net electrical charge of the particle surface (i.e. adsorbent's surface) is equal to zero. This concept has been introduced in the studies dealing with colloidal flocculation to explain why pH is affecting the phenomenon. A related concept in electrochemistry is the electrode potential at the point of zero charge. Generally, the pzc in electrochemistry is the value of the negative decimal logarithm of the activity of the potential-determining ion in the bulk fluid. IUPAC Gold Book The pzc is of fundamental importance in surface science. For example, in the field of environmental science, it determines how easily a substrate is able to adsorb potentially harmful ions. It also has countless applications in technology of colloids, e.g., flotation of minerals. Therefore, the pzc value has been examined in many application of adsorption to the environmental science. The pzc value is typically obtained by t ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Mercury (element)
Mercury is a chemical element; it has Symbol (chemistry), symbol Hg and atomic number 80. It is commonly known as quicksilver. A Heavy metal element, heavy, silvery d-block element, mercury is the only metallic element that is known to be liquid at standard temperature and pressure; the only other element that is liquid under these conditions is the halogen bromine, though metals such as caesium, gallium, and rubidium melt just above room temperature. Mercury occurs in deposits throughout the world mostly as cinnabar (mercuric sulfide). The red pigment vermilion is obtained by Mill (grinding), grinding natural cinnabar or synthetic mercuric sulfide. Exposure to mercury and mercury-containing organic compounds is toxic to the nervous system, immune system and kidneys of humans and other animals; mercury poisoning can result from exposure to water-soluble forms of mercury (such as mercuric chloride or methylmercury) either directly or through mechanisms of biomagnification. Mercu ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Ideal Electrode
In electrochemistry, there are two types of ideal electrode, the ideal polarizable electrode and the ideal non-polarizable electrode. Simply put, the ideal polarizable electrode is characterized by charge separation at the electrode-electrolyte boundary and is electrically equivalent to a capacitor, while the ideal non-polarizable electrode is characterized by no charge separation and is electrically equivalent to a short. Ideal polarizable electrode An ideal polarizable electrode (also ideally polarizable electrode or ideally polarized electrode or IPE) is a hypothetical electrode characterized by an absence of net DC current between the two sides of the electrical double layer, i.e., no faradic current exists between the electrode surface and the electrolyte. Any transient current that may be flowing is considered non-faradaic.Vladimir Sergeevich Bagot'skiĭ, "Fundamentals Of Electrochemistry", John Wiley & Sons, 2006, p. 178. The reason for this behavior is that the electrod ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Volta Potential
The Volta potential (also called Volta effect, Volta potential difference, contact potential difference, outer potential difference, Δψ, or "delta psi") in electrochemistry, is the electrostatic potential difference between two metals (or one metal and one electrolyte) that are in contact and are in thermodynamic equilibrium. Specifically, it is the potential difference between a point close to the surface of the first metal and a point close to the surface of the second metal (or electrolyte). The Volta potential is named after Alessandro Volta. Description When two metals are electrically isolated from each other, an arbitrary potential difference may exist between them. However, when two different neutral metal surfaces are brought into electrical contact (even indirectly, say, through a long electro-conductive wire), electrons will flow from the metal with the higher Fermi level to the metal with the lower Fermi level until the Fermi levels in the two phases are equal. On ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Work Function
In solid-state physics, the work function (sometimes spelled workfunction) is the minimum thermodynamic work (i.e., energy) needed to remove an electron from a solid to a point in the vacuum immediately outside the solid surface. Here "immediately" means that the final electron position is far from the surface on the atomic scale, but still too close to the solid to be influenced by ambient electric fields in the vacuum. The work function is not a characteristic of a bulk material, but rather a property of the surface of the material (depending on crystal face and contamination). Definition The work function for a given surface is defined by the difference :W = -e\phi - E_, where is the charge of an electron, is the electrostatic potential in the vacuum nearby the surface, and is the Fermi level (electrochemical potential of electrons) inside the material. The term is the energy of an electron at rest in the vacuum nearby the surface. In practice, one directly controls ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Solvated Electron
A solvated electron is a free electron in a solution, in which it behaves like an anion. An electron's being solvated in a solution means it is bound by the solution. The notation for a solvated electron in formulas of chemical reactions is "e−". Often, discussions of solvated electrons focus on their solutions in ammonia, which are stable for days, but solvated electrons also occur in water and many other solventsin fact, in any solvent that mediates outer-sphere electron transfer. Solvated electrons are responsible for a great deal of radiation chemistry. Salts containing solvated electrons are known as electrides. Ammonia solutions Liquid ammonia will dissolve all of the alkali metals and other electropositive metals such as Ca, Sr, Ba, Eu, and Yb (also Mg using an electrolytic process), giving characteristic blue solutions. For alkali metals in liquid ammonia, the solution is blue when dilute and copper-colored when more concentrated (> 3 molar). These solution ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
