Equilibrium of mercury

Sommar, J., Lindqvist, 0.. and Stromberg, D. Distribution equilibrium of mercury (11) chloridebetween water and air applied to flue gas scrubbing. J. Air Waste Manage. Assoc., 50(9) 1663-1666, 2000. 

Finally, the cycle which summarizes the equilibrium of mercury in nature is presented. The cycle can be considered closed through the physical transfer of mercury in deep sea sediments to the continents by plate tectonics, where mercury will eventually be remobilized by magmatic heat, erosion, and mining. Since some of the geological and chemical terms may be unfamiliar to the reader, a glossary is included. 

Thus, at equilibrium, aqueous solutions of mercury(I) salts will contain around 0.6% of mercury(II) and the rather finely balanced equilibrium is easily displaced. The presence of any reagent which reduces the activity (in effect the concentration) of Hg + more than that of Hg2 ", either by forming a less-soluble... 

This chart is applicable only to flammable liquids or gases in equilibrium In a closed container. Mixtures of vapor and air will be too lean to burn at temperatures below and at pressures above the values shown by the line on the chart for any substance. Conditions represented by points to the left of and above the respective lines are accordingly nonflammable. Points where the diagonal lines cross the zero gauge pressure line (760 mm of mercury absolute pressure) indicate flash point temperatures at normal atmospheric pressure. 

If it is assumed that the interface between mercury (which is widely used as an electrode for studies of the e.d.l.) and an electrolyte solution forms the two plates of a capacitor, then at equilibrium the mercury plate will have an excess charge and the solution plate a charge of equal magnitude but opposite sign q, and the capacitance C is given by... 

Use the information in Appendix 2B to determine the equilibrium constant for the disproportionation of mercury(I)... 

Since the rate does not display an inverse dependence on Hg(II) concentration, the oxidation of Hg atoms, in equilibrium with mercury(l) and mercury(II), can be discounted, although Hg atoms are kinetically important in the reduction of thallium(IIl) by mercury(I) . It seems likely that the acid-dependent path (A ) involves CoOH. Anion effects were not investigated. 

In contrast to the equilibrium electrode potential, the mixed potential is given by a non-equilibrium state of two different electrode processes and is accompanied by a spontaneous change in the system. Besides an electrode reaction, the rate-controlling step of one of these processes can be a transport process. For example, in the dissolution of mercury in nitric acid, the cathodic process is the reduction of nitric acid to nitrous acid and the anodic process is the ionization of mercury. The anodic process is controlled by the transport of mercuric ions from the electrode this process is accelerated, for example, by stirring (see Fig. 5.54B), resulting in a shift of the mixed potential to a more negative value, E mix. 

The reactions of mercury(II) salts with oligo-amines afford informative examples for the fact that counterions induce the formation of a distinct complex or select a distinct complex in an equilibrium to crystallize with. Thus, Hg11 acetate with dien under exactly the same reaction conditions, in the presence of C104- or PF6-, yields the dinuclear complex [Hg2(dien)3](C104)4 or the mononuclear species [Hg(dien)(H20)](PF6)2, respectively, both characterized by IR, H, and 13C NMR spectrometries, by fast-atom bombardment (FAB) MS, cyclovoltammetry, and X-ray structure analyses.209 In the first compound Pna2, Z = 4), one Hg adopts five-coordination with one tridentate and one bidentate dien ligand, which with the remaining N-donor binds to the... 

As an example of an equilibrium calculation accounting for surface complexation, we consider the sorption of mercury, lead, and sulfate onto hydrous ferric oxide at pH 4 and 8. We use ferric hydroxide [Fe(OH)3] precipitate from the LLNL database to represent in the calculation hydrous ferric oxide (FeOOH /1H2O). Following Dzombak and Morel (1990), we assume a sorbing surface area of 600 m2 g-1 and site densities for the weakly and strongly binding sites, respectively, of 0.2 and 0.005 mol (mol FeOOH)-1. We choose a system containing 1 kg of solvent water (the default) in contact with 1 g of ferric hydroxide. 

A solution was placed in the vessel, CDE, and drops of mercury from A and B allowed to fall through the solution for some hours, the head of mercury being maintained nearly constant. The mercury collected in E and, as the drops coalesced, the surface was reduced and the adsorbed substancejliberated. The constriction at F was provided to prevent diffusion of this released substance backwards into C. It was found that the equilibrium was attained, i.e., that the drops had adsorbed the maximum amount of solute, if they took about six seconds... 

Equilibrium dialysis of homogenates of kidneys of rats given mercuric chloride, revealed that over 99% of the mercury was not diffusible [40]. Diffusible compounds of mercury have the opportunity to cross the capillary membrane and enter the tissue spaces however, due to chemical affinities for cellular binding sites and the diffusible complex, and the ability to penetrate the cell membrane, not all diffusible complexes of mercury present in plasma lead to tissue accumulation. 

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