Carbon dissociative

If the acid of the salt is also volatile, as in the chloride and the carbonate, dissociation occurs causing the salt to sublime ... 

Johnson and Gallagher [410] showed that, in finely divided powder mixtures, Li2C03 and Fe203 react significantly below the usual temperature of carbonate dissociation, so that C02 evolution can be used in kinetic studies of the solid state reaction... 

Kust (4) has potentiometrically determined the equilibrium constant for carbonate dissociation in fused sodium-potassium nitrate eutectic ... 

For a reaction with positive gas mole change, Eq. (47) indicates that Kx decreases with pressure. Because ce is a monotonically increasing function of Kx, the equilibrium extent of a reaction with positive Avgas always decreases as pressure is increased. This is an example of Le Chatelier s principle, which states that a reaction at equilibrium shifts in response to a change in external conditions in a way that moderates the change. In this case, because the reaction increases the number of moles of gas and thus the pressure, the reaction shifts back to reactants. The isothermal compressibility of a reactive system can, therefore, be much greater than that of a nonreactive system. This effect can be dramatic in systems with condensed phases. For example, in the calcium carbonate dissociation discussed in Example 12, if the external pressure is raised above the dissociation pressure of C02, the system will compress down to the volume of the solid. Of course, a similar effect is observed in simple vaporization or sublimation equilibrium. As the pressure on water at 100°C is increased above 1.0 atm, all vapor is removed from the system. 

The C02 produced by the decomposition of a carbonate dissociates partly to CO and 02. However, at temperatures for which most of the carbonate equilibria have been calculated, the decomposition of C02 is very slight. Therefore, the decomposition equilibria for carbonates have been given in terms of C02 only. However, for those wishing to refine the calculations, thermodynamic functions for the three gases and the equilibrium constant for the reaction C02 = CO + 02 have been listed... 

Suppose to start with that the carbonate dissociates in an enclosure empty at first the system is divided into two phases, the solid carbonate and the gaseous mixture it contains, further more, but a single independent component, for each molecule of carbonic anhydride which it contains is accompanied by two molecules of ammonia if the mass of the first substance it contains is known, in the free state or in combination, the mass of second substance contained in it is also known e system is therefore monovariant at each temperature T equilibrium is maintained by a well-determined pressure n. 

Wanninkhof R., Lewis E., Eeely R. A., and MiUero E. J. (1999) The optimal carbonate dissociation constants for determining surface water pC02 from alkalinity and total inorganic carbon. Mar. Chem. 65, 291-301. 

However, there is no way to know how much this would affect the COg concentration formed by the second carbonate dissociation reaction... 

Another interesting aspect of the model reactions has been reported for copper-mediated processes.273 Thus, optically active methyl 2-bromopropionate was mixed with a CuCl catalyst, and the reaction was followed by NMR and polarimetry. The latter analysis showed, as in solvolysis, that the model quickly undergoes racemization i.e., the halogen on the chiral carbon dissociates and recouples. 

Many solid state reactions are reversible. Examples include the endothermic dehydrations and carbonate dissociations [67] such as ... 

Nucleation appears to occur readily in most carbonate dissociations. Product recrystallization may occur only after COj release as shown for CaCO, [3,4] and basic nickel carbonate [71]. There is little evidence for promotion of the interface reaction by the solid product, instead the solid product is an inhibitor through increasing the contribution of the reverese (recombination) process. Measured values of are usually comparable with reaction enthalpies (Table 12.1.). Together these features suggest that the rates of most carbonate dissociations are controlled by anion breakdown at the boundaries of reactant particles. 

While this series of reactions is possible, much higher temperatures are required for sodium carbonate dissociation to sodium oxide and carbon... 

The alkalinity and DIC data were used to calculate the carbonate ion concentration and pH of the culture medium during the second half of the first experiment, and throughout the second experiment (Fig. 3). These calculations used the program C02SYS (Lewis Wallace 1998) with the carbonate dissociation constants of Roy et al. (1993), the calcite solubility of Mucci (1983), and the assumption that the boron/salinity ratio of the culture system water was equal to the seawater ratio. Because much of the culture system water in both years was Instant Ocean, it may not be correct to estimate the total borate concentration from the whole-ocean boron/salinity relationship. However, trends in the concentrations of carbonate system species during each year will be independent of the actual absolute total borate concentration. 

Deaeration is accompanied by some reduction of carbon dioxide content, particularly if the water is acidified before the deaeration process to liberate carbonic acid from the dissolved carbonates. Carbonic acid is corrosive to steel in the absence of dissolved oxygen and more so in its presence [18], but addition of alkali to boiler water limits any corrosion caused by carbon dioxide to the boiler itself by converting dissolved carbon dioxide to carbonates. At prevailing boiler temperatures, however, carbonates dissociate as follows ... 

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