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Koutecký–Levich Equation
The Koutecký–Levich equation models the measured electric current at an electrode from an electrochemical reaction in relation to the kinetic activity and the mass transport of reactants. The Koutecký–Levich equation can be written as'':'' =+ where * ''i''m is the measured current (A). * ''i''K is the kinetic current (A) from the electrochemical reactions. * ''i''MT is the mass transport current (A). Note the similarity of this equation to the conductance of an electrical circuits in parallel. The Koutecký–Levich equation is also commonly expressed as: i_m= The kinetic current (''i''K) can be modeled by the Butler-Volmer Equation and is characterized by being potential dependent. On the other hand, the mass transport current (''i''MT) depends on the particular electrochemical setup and amount of stirring. Koutecký–Levich plot In the case a rotating disk electrode setup is used and the electrode is flat and smooth, the ''i''MT can modeled using the Le ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Electric Current
An electric current is a stream of charged particles, such as electrons or ions, moving through an electrical conductor or space. It is measured as the net rate of flow of electric charge through a surface or into a control volume. The moving particles are called charge carriers, which may be one of several types of particles, depending on the conductor. In electric circuits the charge carriers are often electrons moving through a wire. In semiconductors they can be electrons or holes. In an electrolyte the charge carriers are ions, while in plasma, an ionized gas, they are ions and electrons. The SI unit of electric current is the ampere, or ''amp'', which is the flow of electric charge across a surface at the rate of one coulomb per second. The ampere (symbol: A) is an SI base unit. Electric current is measured using a device called an ammeter. Electric currents create magnetic fields, which are used in motors, generators, inductors, and transformers. In ordinary con ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Electrode
An electrode is an electrical conductor used to make contact with a nonmetallic part of a circuit (e.g. a semiconductor, an electrolyte, a vacuum or air). Electrodes are essential parts of batteries that can consist of a variety of materials depending on the type of battery. The electrophore, invented by Johan Wilcke, was an early version of an electrode used to study static electricity. Anode and cathode in electrochemical cells Electrodes are an essential part of any battery. The first electrochemical battery made was devised by Alessandro Volta and was aptly named the Voltaic cell. This battery consisted of a stack of copper and zinc electrodes separated by brine-soaked paper disks. Due to fluctuation in the voltage provided by the voltaic cell it wasn't very practical. The first practical battery was invented in 1839 and named the Daniell cell after John Frederic Daniell. Still making use of the zinc–copper electrode combination. Since then many more batteries have be ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Electrochemical Reaction
Electrochemistry is the branch of physical chemistry concerned with the relationship between electrical potential difference, as a measurable and quantitative phenomenon, and identifiable chemical change, with the potential difference as an outcome of a particular chemical change, or vice versa. 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 af ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Kinetic Activity
Kinetic (Ancient Greek: κίνησις “kinesis”, movement or to move) may refer to: * Kinetic theory, describing a gas as particles in random motion * Kinetic energy, the energy of an object that it possesses due to its motion Art and entertainment * Kinetic art, a form of art involving mechanical and/or random movement, including optical illusions. * ''Kinetic'', the 13th episode of the first season of the TV series ''Smallville'' * ''Kinetic'' (comics), a comic by Allan Heinberg and Kelley Pucklett * "Kinetic" (song), a song by Radiohead Companies * Kinetic Engineering Limited, Indian automotive manufacturer * Kinetic Group, Australian-based public transport company Technology * "Kinetic", Seiko's trademark for its automatic quartz technology * The ''Kinetic camera system'' by Birt Acres (1854–1918), photographer and film pioneer * Kinetic projectile Military terminology * Kinetic military action See also * * * Kinetics (other) * Dynamics (disambiguatio ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Mass Transfer
Mass transfer is the net movement of mass from one location (usually meaning stream, phase, fraction or component) to another. Mass transfer occurs in many processes, such as absorption, evaporation, drying, precipitation, membrane filtration, and distillation. Mass transfer is used by different scientific disciplines for different processes and mechanisms. The phrase is commonly used in engineering for physical processes that involve diffusive and convective transport of chemical species within physical systems. Some common examples of mass transfer processes are the evaporation of water from a pond to the atmosphere, the purification of blood in the kidneys and liver, and the distillation of alcohol. In industrial processes, mass transfer operations include separation of chemical components in distillation columns, absorbers such as scrubbers or stripping, adsorbers such as activated carbon beds, and liquid-liquid extraction. Mass transfer is often coupled to additional tr ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Measured Current Vs Mass Transport And Kinetic Current Plot
Measurement is the quantification of attributes of an object or event, which can be used to compare with other objects or events. In other words, measurement is a process of determining how large or small a physical quantity is as compared to a basic reference quantity of the same kind. The scope and application of measurement are dependent on the context and discipline. In natural sciences and engineering, measurements do not apply to nominal properties of objects or events, which is consistent with the guidelines of the ''International vocabulary of metrology'' published by the International Bureau of Weights and Measures. However, in other fields such as statistics as well as the social and behavioural sciences, measurements can have multiple levels, which would include nominal, ordinal, interval and ratio scales. Measurement is a cornerstone of trade, science, technology and quantitative research in many disciplines. Historically, many measurement systems existed for t ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Series And Parallel Circuits
Two-terminal components and electrical networks can be connected in series or parallel. The resulting electrical network will have two terminals, and itself can participate in a series or parallel topology. Whether a two-terminal "object" is an electrical component (e.g. a resistor) or an electrical network (e.g. resistors in series) is a matter of perspective. This article will use "component" to refer to a two-terminal "object" that participate in the series/parallel networks. Components connected in series are connected along a single "electrical path", and each component has the same current through it, equal to the current through the network. The voltage across the network is equal to the sum of the voltages across each component. Components connected in parallel are connected along multiple paths, and each component has the same voltage across it, equal to the voltage across the network. The current through the network is equal to the sum of the currents through each com ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Rotating Disk Electrode
A rotating disk electrode (RDE) is a working electrode used in three electrode systems for hydrodynamic voltammetry.Bard, A.J.; Faulkner, L.R. Electrochemical Methods: Fundamentals and Applications. New York: John Wiley & Sons, 2nd Edition, 2000. The electrode rotates during experiments inducing a flux of analyte to the electrode. These working electrodes are used in electrochemical studies when investigating reaction mechanisms related to redox chemistry, among other chemical phenomena. The more complex rotating ring-disk electrode can be used as a rotating disk electrode if the ring is left inactive during the experiment. Structure The electrode includes a conductive disk embedded in an inert non-conductive polymer or resin that can be attached to an electric motor that has very fine control of the electrode's rotation rate. The disk, like any working electrode, is generally made of a noble metal or glassy carbon, however any conductive material can be used based on specifi ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Levich Equation
The Levich equation models the diffusion and solution flow conditions around a rotating disk electrode (RDE). It is named after Veniamin Grigorievich Levich who first developed an RDE as a tool for electrochemical research. It can be used to predict the current observed at an RDE, in particular, the Levich equation gives the height of the sigmoidal wave observed in rotating disk voltammetry. The sigmoidal wave height is often called the Levich current. Equation The Levich equation is written as: :I_L = (0.620) n F A D^\frac \omega^\fracv^\fracC where ''I''L is the Levich current (A), ''n'' is the number of moles of electrons transferred in the half reaction (number), ''F'' is the Faraday constant (C/mol), ''A'' is the electrode area (cm2), ''D'' is the diffusion coefficient (see Fick's law of diffusion) (cm2/s), ''ω'' is the angular rotation rate of the electrode (rad/s), ''v'' is the kinematic viscosity (cm2/s), ''C'' is the analyte An analyte, component (in clinical chemi ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Levich Constant
A Levich constant (B) is often used in order to simplify the Levich equation. Furthermore, B is readily extracted from rotating disk electrode experimental data. The B can be defined as: B= (0.620) n F A D^\fracv^\fracC where * ''n'' is the number of moles of electrons transferred in the half reaction (number) * ''F'' is the Faraday constant (C/mol) * ''A'' is the electrode area (cm2) * ''D'' is the diffusion coefficient (see Fick's law of diffusion) (cm2/s) * ''v'' is the kinematic viscosity (cm2/s) * ''C'' is the analyte An analyte, component (in clinical chemistry), or chemical species is a substance or chemical constituent that is of interest in an analytical procedure. The purest substances are referred to as analytes, such as 24 karat gold, NaCl, water, etc. ... concentration (mol/cm3) References Electrochemical equations Electrochemistry {{electrochem-stub ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
