Electrolytic cell An electrochemical

ELECTROLYTIC CELL. An electrochemical device in which electrolysis occurs when an electric current is passed through it. lonizable... 

Electrolysis or electrolytic cell. An electrochemical cell through which current is forced by a battery or some other external source of energy. 

Electrolytic cell An electrochemical cell that requires an external source of energy to drive the cell reaction. Compare with galvanic cell. 

Electrolytic cell An electrochemical cell in which electrical energy causes nonspontaneous redox reactions to occur. 

Electrolytic cell - an electrochemical cell in which reactions are driven by the application of an external voltage greater than the spontaneous potential of the ceil. 

Electrolyte a substance, such as sodium chloride, that dissolves in water to give an electrically conducting solution. (4.1) Electrolytic cell an electrochemical cell in which an electric current drives an otherwise nonspontaneous reaction, (p. 808) Electromagnetic spectrum the range of frequencies or wavelengths of electromagnetic radiation. (7.1)... 

Electrolytic Cell An electrochemical cell with forced reactions to promote... 

Measurement of electrical potential differences requires a complete electrical circuit, i.e., the electrochemical cell. An electrochemical galvanic cell consisting of all conducting phases, and among them at least one interface separating two immiscible electrolyte solutions is called for short a liquid galvanic cell. In contrast, the system composed of con-... 

Electrochemical cells produce electrical energy from a spontaneous chemical reaction. In electrolysis, the process is reversed so that electrical energy is used to carry out a nonspontaneous chemical change. A cell arranged to do this is called an electrolytic cell. An electrolytic cell is similar to an electrochemical cell except that an electrolytic cell s circuit includes a power source, for example, a battery. The same electrochemical cell terminology applies to electrolytic cells. Reduction occurs at the cathode and oxidation at the anode. 

According to Birss and Truax (72), students are likely to experience confusion and difficulty with more advanced treatments of the subject. With regard to conceptual difficulties, the authors looked at the equilibrium potential, the reversal of sign of electrode reactions that are written as oxidations, and the differences between galvanic (electrochemical) and electrolytic cells. An approach for teaching these topics at the freshman level was then proposed. In this approach, concepts from thermodynamics and chemical kinetics are interwoven with those of electrochemical measurements. Very useful are... 

Suitable solid electrolytes can be employed as the electrolyte in an electrochemical cell. The electrolyte is used in the form of a membrane which is impermeable to gas phase transport. Electroactive materials, or electrodes, are deposited on both sides of the electrolyte to increase the rates of charge transfer across the electrolyte interface and it is important that the active molecules in the gas phase have easy access to the electrode/electrolyte interface where they can participate in the charge-transfer reactions. For this reason it is necessary, in most cases, to ensure that the electrode has a high porosity while, at the same time, remaining electrically continuous. 

A battery (or galvanic or voltaic cell) is a device that uses oxidation and reduction reactions to produce an electric current. In an electrolytic cell, an external source of electric current is used to drive a chemical reaction. This process is called electrolysis. When the electric potential applied to an electrochemical cell is just sufficient to balance the potential produced by reactions in the cell, we have an electrochemical cell at equilibrium. This state also occurs if there is no connections between the terminals of the cell (open-circuit condition). Our discussion in this chapter will be limited to electrochemical cells at equilibrium. 

Gabrielli and Perrot [23] carried out in situ mass measurements in well-defined flowing electrolyte with an electrochemical quartz crystal microbaiance (EQCM) adapted to a submerged impinging jet cell (wall tube configuration). The authors employed this new device for the study of nickel electrodeposition and evaluation of the cathodic efficiency. Under the conditions of their experiment (nozzle diameter d = 7 mm disc electrode diameter de = 5 mm and nozzle-to-electrode distance H = 2d), the current that flows at the electrode increases with the square root of flow rate (0-10 cm3 s"1). It should be noted that this approach is much simpler to implement than the rotating EQCM, while keeping control of the convective-diffusion conditions. 

Fuel cell An electrochemical energy conversion device. It produces electricity from various external quantities of fuel (on the anode side) and oxidant (on the cathode side). These react in the presence of an electrolyte. Fuel cells are different from batteries in that they consume reactant, which must be replenished, while batteries store electrical energy chemically in a closed system... 

A flashlight battery is an electrochemical cell. An electrochemical cell consists of two electrodes separated by an electrolyte. An electrode is a conductor that connects with a nonmetallic part of a circuit. You have learned about two kinds of conductors. One kind includes metals, which conduct electric current through moving electrons. The second kind includes electrolyte solutions, which conduct through moving ions. 

Electrolysis refers to the chemical reaction or reactions that accompany the passage of a current supplied by an external source through an electrolytic solution. An electrochemical cell through which a current is passing is said to be polarized. Polarization is a general term that refers to any or all of the phenomena associated with the passage of a current through a cell. 

Two different metals that are connected and immersed in an electrolyte form an electrochemical cell. If a current is allowed to flow, one metal will be consumed and one will remain the same or be increased in some way. These processes lead to dissimilar metal corrosion. In order for dissimilar metal corrosion to occur, it is necessary to have an anode, a cathode, an electrolyte and a connection from anode to cathode. The anode component corrodes whereas the cathode remains unattacked. The tendency for such reactions to take place spontaneously can be judged from the electrochemical series. Three examples follow. 

Fig. 3.3 Illustration of the potential gradient (voltage drop) across the electrolyte in an electrochemical cell. A Luggin capillary can be used to ensure that the reference electrode measures the potential close to the working electrode surface, i.e., < ref instead of j gp...

A number of analytical methods are based on electrochemical properties in solutions. If, for example, two metallic conductors are immersed in an electrolyte solution, current can flow when an electric potential is applied. If two different metals are present in the electrolytic cell, an electric potential can be tapped. Its force is dependent on the type of electrode materials and on the composition of the solution, on the gap between the electrodes and on the electrode surface. 

Abstract This chapter is dedicated to some significant applications of membranes in the field of energy, focusing on fuel cells and electrolytic cells. Both electrochemical devices are part of an international effort at both fundamental and demonstration levels and, in some specific cases, market entry has already begun. Membranes can be considered as separators between cathodes and anodes. As fuel cells are extremely varied, with working temperatures between 80°C and 900°C, and electrolytes from liquid to solid passing by molten salts, they are of particular interest for the research and development of new membranes. The situation is quite similar to the case of electrolysers dedicated to water electrolysis. The principal features of these devices will be outlined, with emphasis on the properties of the state-of-the-art membranes and on the present innovations in this area. 

There are several companies, including the AEA technology division at Dounreay, developing a process, based on a silver salt/nitric acid electrolyte and an electrochemical membrane cell, for destroying organic hazardous wastes [79]. At the anode of the cell a very highly reactive chemical species of Ag(II) or the free radical(s) generated from the reaction of Ag(II) ions with water is produced ... 

It is well known today that perhaps the most dramatic application of the fuel cell—an electrochemical device that may be based in the future upon the oxidation of aliphatic hydrocarbons— was in the Gemini Space Mission. In this application, the cell was based upon the use of a solid polymer electrolyte —a cation-exchange membrane in its acid form—but with hydrogen and oxygen as the fuels rather than an aliphatic hydrocarbon. Considerable research and development preceded and supported these successful missions and the units demonstrated that indeed the H2/O2 fuel cell was capable of extended performance at relatively high current densities—2l capability of fundamental importance in commercial applications. 

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