Gases equilibria involving

Solid-gas equilibriums involving electron transfers or electron holes... 

Solid-gas equilibriums involving mass and charge transfers... 

A number of metals have the ability to absorb hydrogen, which may be taken into solid solution or form a metallic hydride, and this absorption can provide an alternative reaction path to the desorption of H,. as gas. In the case of iron and iron alloys, both hydrogen adsorption and absorption occur simultaneously, and the latter thus gives rise to another equilibrium involving the transfer of H,<,s across the interface to form interstitial H atoms just beneath the surface ... 

Thus we see that the equilibrium solubility of a gas again involves a balance between randomness and energy as it does for a solid, but the effects are opposite. For a gas, the tendency toward maximum randomness favors the gas phase, opposing dissolving. The tendency toward minimum energy favors the liquid state, hence favors dissolving. 

Gas These are constructed by placing a strip of nonreactive metals (usually platinum or gold) in contact with both the solution and a gas stream (a) the hydrogen electrode consists of a platinum strip exposed to a current of hydrogen, and partly immersed in an acid solution. A potential is set up between the gas and the solution, the equilibrium involved being H2 2H + 2 e (b) potentials also occur when the halogens are in contact with their ions in solution, the equilibrium in the case of chlorine being Cl2 + 2 e- 2 Cl". 

At room temperature, I would expect to find the sealed container with the iodine crystals filled with a lightly purplish gas (iodine vapor) and tiny crystals of iodine on the inside walls and top of the container where the iodine gas redeposited. The equilibrium involved here is... 

A heterogeneous phase equilibrium involving a gas phase represents a convenient way of determining the Gibbs energy of a substance. A substance may evaporate congruently ... 

The worst deviations from the Clapeyron equation occur when one of the phases is a gas. This occurs because the volume of a gas depends strongly on temperature, whereas the volume of a liquid or solid does not. Accordingly, the value of A Vm is not independent of temperature when the equilibrium involves a gas. 

The purpose of this chapter is to outline the simplest methods of arriving at a description of the distribution of species in mixtures of liquids, gases and solids. Homogeneous equilibrium deals with single phase systems, such as electrolyte solutions (e.g., seawater) or gas mixtures (e.g., a volcanic gas). Heterogeneous equilibrium involves coexisting gaseous, liquid and solid phases. 

We can generalize from this example and say that, for any chemical equilibrium involving a different number of moles of gas on each side of the balanced equation, the equilibrium position will always shift with an increase in total pressure toward the side with the smaller number of gaseous moles the value ofXp will remain unchanged. 

Thus, complete establishment of adsorption equilibrium involves two fundamentally different processes the adsorption of gas on a surface in a given state with a given distribution, p(E), and the change of the surface due to the presence of the adsorbed substance, which induces a tendency towards a new equilibrium distribution p(E, q), where q is the quantity of adsorbed matter. 

We now use A as the total primary dopant concentration (e.g., the donor) and link it to the charge transfer from the gas molecules through the electron-exchange equilibrium. The ionization equilibrium involving this level is... 

In general, the initially formed formyl, hydroxycarbonyl or nitrito-carbonyl complexes rapidly convert to hydrido or nitrosyl complexes with elimination of CO or C02 however, occasionally intermediates have been isolated. The oxidation of coordinated CO to C02 by amine oxides (Figure 3.15) may be considered a further example. The hydroxycarbonyl example underpins a technologically important process, the water-gas shift equilibrium, involving the catalytic conversion of CO and water into CO, and hydrogen (Figures 3.22, 3.11 and 2.13). 

An important aspect of the design of an acid gas injection scheme is the non-aqueous phase equilibrium. Fluid phase equilibrium involving water, which is also very important, will be discussed in chapter 4 and hydrates in chapter 5. 

The calculation of temperatures and equilibrium compositions of gas mixtures involves simultaneous solution of linear (material balance) and nonlinear (equilibrium) algebraic equations. Therefore, it is necessary to resort to various approximate procedures classified by Carter and Altman (Cl) as (1) trial and error methods (2) iterative methods (3) graphical methods and use of published tables and (4) punched-card or machine methods. Numerical solutions involve a four-step sequence described by Penner (P4). 

Although fractionations of 60-80%o are theoretically possible under equilibrium conditions at very low temperatures ( 0 °C), they are not observed on Earth. Urey (1967) therefore proposed that the two types of carbon came from two unrelated reservoirs, whereas Arrhenius and Alfven (1971) suggested fractionation during carbonate growth from the gas phase, involving multiple desorption or metastable molecules. 

Only such processes as involve oxidation will be considered here. These processes result in the formation of hydrogen and carbon monoxide directly or hydrogen and carbon dioxide indirectly through the water-gas equilibrium. 

Wienhoffer and Gopel have defined a number of modes of operation [67], One is the direct participation of the mobile ion in the electrochemical equilibrium involving the gas of interest. Thus the mobile oxygen dianion in zirconia is in equilibrium with gaseous oxygen ... 

Gas chromatography involves the same two types of phenomena as any chromatographic method first, static or equilibrium processes that can be described thermodynamically second, dynamic or flux processes (including mass-transport) that must be described kinetically. A rudimentary understanding of both statics and dynamics as they apply to gas chromatography should help the student to understand the potential and limitations of this technique and to improve his or her attack on a problem in analysis. In this section, the static aspects are considered. 

In this book, we will first explore solid-gas equilibriums and distingirish between the equilibriums that only involve electron transfers and/or electron holes and those that involve charge and mass transfers. 

Calculations of vapor-liquid equilibrium involving a gas dissolved in a liquid are performed using the Lewis-Randall rule for the fugacity of the liquid phase and Henry s law for the vapor phase. Using the subscript s for the solvent, and i for the gas, the equilibrium criterion for the two components is. 

If the substance in the state of interest is a hquid or gas, or a crystal of a different form than the perfectly-ordered crystal present at zero kelvins, the heating process will include one or more equilibrium phase transitions under conditions where two phases are in equilibrium at the same temperature and pressure (Sec. 2.2.2). For example, a reversible heating process at a pressure above the triple point that transforms the crystal at 0 K to a gas may involve transitions from one crystal form to another, and also melting and vaporization transitions. 

When chemical equilibrium is established in one phase- a mixture of gases, a liquid solution-we have a case of HOMOGENEOUS EQUiLIB-RiUM. An equilibrium involving more than one phase-gas and solid, for example, or liquid and solid-is said to be HETEROGENEOUS. A saturated solution in equilibrium with solute is a familiar instance of heterogeneous equilibrium. For the present we shall concern ourselves with gas-solid reactions. 

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