Activity electrolyte

Reserve batteries have been developed for appHcations that require a long inactive shelf period foUowed by intense discharge during which high energy and power, and sometimes operation at low ambient temperature, are required. These batteries are usually classified by the mechanism of activation which is employed. There are water-activated batteries that utilize fresh or seawater electrolyte-activated batteries, some using the complete electrolyte, some only the solvent gas-activated batteries where the gas is used as either an active cathode material or part of the electrolyte and heat-activated or thermal batteries which use a soHd salt electrolyte activated by melting on appHcation of heat. 

Anodes similar to cables are used which consist of a copper conductor covered with conducting plastic. This creates an electrolytically active anode surface and at the same time protects the copper conductor from anodic dissolution. 

Like its chemical potential, the activity of an individnal ion cannot be determined from experimental data. For this reason the parameters of electrolyte activity % and mean ionic activity are nsed, which are defined as follows ... 

The thermodynamic properties of real electrolyte solutions can be described by various parameters the solvent s activity Oq, the solute s activity the mean ion activities a+, as well as the corresponding activity coefficients. Two approaches exist for determining the activity of an electrolyte in solution (1) by measuring the solvent s activity and subsequently converting it to electrolyte activity via the thermodynamic Gibbs-Duhem equation, which for binary solutions can be written as... 

Expressing the distribution constant in terms of the mean electrolyte activities one obtains ... 

Rard also employed Pitzer s electrolyte activity coefficient model to correlate the data. It was found that the quality of the fit depended on the range of molalities that were used. In particular, the fit was very good when the molalities were less than 3 mol/kg. 

Estimate Pitzer s electrolyte activity coefficient model by minimizing the objective function given by Equation 15.1 and using the following osmotic coefficient data from Rard (1992) given in Table 15.5. First, use the data for molalities less than 3 mol/kg and then all the data together. Compare your estimated values with those reported by Rard (1992). Use a constant value for in Equation 15.1. 

Thiessen, D.B., and Wilson, "An Isopiestic method for Measurement of Electrolyte Activity Coefficients", AIChE J., 33(11), 1926-1929, 1987. 

Once the composition of the aqueous solution phase has been determined, the activity of an electrolyte having the same chemical formula as the assumed precipitate can be calculated (11,12). This calculation may utilize either mean ionic activity coefficients and total concentrations of the ions in the electrolyte, or single-ion activity coefficients and free-species concentrations of the ions in the electrolyte (11). If the latter approach is used, the computed electrolyte activity is termed an ion-activity product (12). Regardless of which approach is adopted, the calculated electrolyte activity is compared to the solubility product constant of the assumed precipitate as a test for the existence of the solid phase. If the calculated ion-activity product is smaller than the candidate solubility product constant, the corresponding solid phase is concluded not to have formed in the time period of the solubility measurements. Ihis judgment must be tempered, of course, in light of the precision with which both electrolyte activities and solubility product constants can be determined (12). 

A very fine example was provided by the extensive use of Professor Pitzer s electrolyte activity coefficient theory within several acid gas phase equilibrium models. 

Electrolyte Activities. The activity of a solid electrolyte in equilibrium with its pure saturated solution, by definition is ... 

The success of Harned s rule for ternary solutions is largely fortuitous, and the rule has no theoretical basis to expect that it would be useful for solutions containing more than two electrolytes. Furthermore, for high concentrations of several electrolytes, activity coefficients such as Y3(g are hypothetical. There are, unfortunately, few experimental data available to test Harned s rule for concentrated solutions of three or more electrolytes. 

Thick ascending limb This limb is also impermeable to water. It contains ion pumps to pump electrolytes actively into the interstitium. The main pump is the Na+/2C1 /K+ co-transporter. Fluid leaving this limb is, therefore, hypotonic and passes into the distal convoluted tubule. 

Perhaps more important than cost is the solution to the crucial problem of interfacial contacts that always plagues homogeneous GPE films prepared from traditional approaches. Since both cathode and anode composite materials are coated on their substrates with the same PVdF—HEP copolymer as the binder, the in situ gellification following the electrolyte activation effectively fuses the three cell components into an integrated multilayer wafer without physical boundaries, so that the interfaces between anode and electrolyte or cathode and electrolyte are well extended into the porous structures of these electrodes, with close similarity to the interfaces that a liquid electrolyte would access. 

A unitless correction factor that relates the relative activity of a substance to the quantity of the substance in a mixture. Activity coefficients are frequently determined by emf (electromotive force) or freezing-point depression measurements. At infinite dilution, the activity coefficient equals 1.00. Activity coefficients for electrolytes can vary significantly depending upon the concentration of the electrolyte. Activity coefficients can exceed values of 1.00. For example, a 4.0 molal HCl solution has a coefficient of 1.76 and a 4.0 molal Li Cl has a value of... 

In the same research described in Problem 8, the authors also examined the rate of Reaction (F) in pure water and in NaCl solution to guarantee that the ionic surfactants were not displaying an electrolyte activity effect as is ordinarily observed with ion combination reactions. For 10-5 M crystal violet and 0.01 M NaOH, they observed the following ... 

Here t is the ionic transport number, a is the electrolyte activity, and the subscripts 1 and 2 refer to the left and right sides of the junction. For Omxi = mx2. Ej(i)=0. If the experimental (actual) variations in component (i), obtained by changing the ratio C /c2, are plotted against the values calculated by Eq. (6.16), lin-... 

Gordon, J. E., and R. L. Thorne, Salt effects on non-electrolyte activity coefficients in mixed aqueous electrolyte solutions. II. Artificial and natural sea waters , Geochim. Cosmochim. Acta, 31, 2433-2443 (1967b). 

The history of the ion-pair concept begins in the 1880s [50] with the theory of Arrhenius that described the electrolytic dissociation in solution as a function of electrolyte concentration and nature. This theory was completely eclipsed by the success of the D-H treatment of electrolyte activity in the 1920s [33] that also paved... 

Dependence of the cathodic (Ic) and anodic (1 ) current on the number of coloring-bleaching cycles for the HEC employing ICS-2ME/TEOS/TEG/OXA/NH4I + Ij redox electrolyte (active electrode surface area 4 cm. ... 

As shown in Fig. 7.40, in general, the dissolution of a silicon surface involves three essential species A, etching species such as OH" in the electrolyte , active silicon atoms on the surface and h, charge carriers from the semiconductor. The etch rate of the surface can then be expressed as... 

Overdose may require supportive measures to maintain arterial B/P (monitor cardiac function, vital signs, blood gases, serum electrolytes). Activated charcoal may be more effective than emesis or lavage. 

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