Silver thermodynamic parameters

Another approach to the study of proteins has been the reaction of silver ions with simpler model compounds, for example di- and tri-peptides.416 The reaction with glycylglycine was first studied in 1951 and the formation constants for 1 1 and 1 2 complexes were determined.403 Thermodynamic parameters for these reactions have since been measured (log 0i = 2.90, logp2 = 5.65, AHfo = -56.9 0.8kjmol"1, ASj32 = -80.5 3 JK"1 mol"1).416... 

Much has been written about solid metal electrodes, which have now largely displaced liquid mercury. Those most often used as redox ( inert ) electrodes for studying electron transfer kinetics and mechanism, and determining thermodynamic parameters are platinum, gold, and silver. However, it should be remembered that their inertness is relative at certain values of applied potential bonds are formed between the metal and oxygen or hydrogen in aqueous and some non-aqueous solutions. Platinum also exhibits catalytic properties. 

Electrochemical cells can also be used to determine other thermodynamic parameters such as equilibrium constants. For example, the solubility product for the sparingly soluble salt AgCl may be determined by comparing the properties of the silver silver chloride electrode (9.2.23) with those of the silver silver ion electrode (9.2.39). The potentials of these electrodes are equal when they are in a saturated solution of AgCl, that is, when the activities of these ions are those given by equilibrium (9.2.40). Therefore, under these conditions... 

DAS/SAH] Das, R. C., Sahu, G., Satyanarayana, D., Misra, S. N., Silver-silver selenocyanate electrode determination of standard electrode potential, solubility product of AgSeCN and various thermodynamic parameters at 35, 40, 45 and 50°C, Electrochim. Acta, 19, (1974), 887-890. Cited on page 307. 

Kozlov, V.K., Kuznetsov, V.N., and Khodakovskii, I.L. (1983) The thermodynamic parameters of AgjO and silver(I) hydroxyl complexes in aqueous solutions... 

Hug] Method of distribution copper between liquid silver and C-Cu melts. Thermodynamic calculation of interaction parameters The activity of copper in melt (0 to 25) mass% C-(0 to 25) mass% Cu-Fe, 1550°C... 

An investigation of why hydroxide makes the Tollens silver mirror test for aldehydes more sensitive has focused on thermodynamic versus kinetic factors. Electrochemistry tends to rule out the former the electromotive force (emf) of an appropriate cell changes little with pH. Exploring the kinetics, single electron transfer processes were confirmed by addition of a radical trap (TEMPO), which slowed the reaction. Rate measurements point to the rate of the formation of the anion of the gm-diol (i.e. the hydrate anion) as the key parameter affected by added hydroxide, a factor that also explains how the rapidity of the test varies with the structure of the aldehyde. 

Electrode materials are a key parameter to assure that electron transference takes place at fast rates. Selection of materials should be based on thermodynamic and kinetic response, so interface molecular interactions are fast enough to release the oxidant sp>ecies. Also, it must be considered aspects like mechanical, thermic and corrosion resistance as well as the procedures and solutions used in surface cleaning, pretreatment, and surface activation. In this sense, materials which satisfy these requirements are vitreous carbon, titanium, stainless steel, platinum, gold and silver but it must not be discarded that all materials can... 

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