Oxygen, thermodynamic data

Figure 4.24 Relationship between the partial pressure of oxygen and the composition of CO-CO2 and H2-H2O gas mixtures at 1 bar. (a) Pco PcO-, versus temperature and (b) Pyi2IPw-X) versus temperature at selected partial pressures of oxygen. Thermodynamic data are taken from reference [21].

Flame Temperature. The adiabatic flame temperature, or theoretical flame temperature, is the maximum temperature attained by the products when the reaction goes to completion and the heat fiberated during the reaction is used to raise the temperature of the products. Flame temperatures, as a function of the equivalence ratio, are usually calculated from thermodynamic data when a fuel is burned adiabaticaHy with air. To calculate the adiabatic flame temperature (AFT) without dissociation, for lean to stoichiometric mixtures, complete combustion is assumed. This implies that the products of combustion contain only carbon dioxide, water, nitrogen, oxygen, and sulfur dioxide. 

The thermodynamic data pertinent to the corrosion of metals in aqueous media have been systematically assembled in a form that has become known as Pourbaix diagrams (11). The data include the potential and pH dependence of metal, metal oxide, and metal hydroxide reactions and, in some cases, complex ions. The potential and pH dependence of the hydrogen and oxygen reactions are also suppHed because these are the common corrosion cathodic reactions. The Pourbaix diagram for the iron—water system is given as Figure 1. 

Fig. 7.67 Phase stability diagram for a metal-sulphur-oxygen (M-S-O) system at I 000 K. (For the thermodynamic data AC 000 for the various across-boundary reactions, see Table 7.37)...

This paper reviews data on certain thermodynamic aspects of the nonstoichiometric Pu-0 system, which may serve as a basis for use In reactor safety analysis. Emphasis Is placed on phase relationships, vaporization behavior, oxygen-potential measurements, and evaluation of pertinent thermodynamic quantities. Limited high temperature oxygen potential data obtained above the fluorite, diphasic, and sesquioxide phases In the Pu-0 system are presented. 

Little work has been carried out using electrochemical cells to analyze for impurities. Thermodynamic data have been measured for the interaction of nuclear fuels with liquid potassium using cells based on ThOj-YjOj electrolytes, so such cells could be used to monitor oxygen. Both the diffusion and electrochemical types of hydrogen and carbon meters should function satisfactorily in liquid potassium. 

Oxygen gas has many applications, from welders torches to respirators. The gas is sold commercially in pressurized steel tanks. One such tank contains O2 at p = 6.50 bar and T — 298 K. Using standard thermodynamic data, compute the molar entropy of the gas in the tank at 6.50 bar and the change in entropy of a 0.155-mol sample of gas withdrawn from the tank at 1.10 bar and constant temperature. 

The mixed-potential model demonstrated the importance of electrode potential in flotation systems. The mixed potential or rest potential of an electrode provides information to determine the identity of the reactions that take place at the mineral surface and the rates of these processes. One approach is to compare the measured rest potential with equilibrium potential for various processes derived from thermodynamic data. Allison et al. (1971,1972) considered that a necessary condition for the electrochemical formation of dithiolate at the mineral surface is that the measmed mixed potential arising from the reduction of oxygen and the oxidation of this collector at the surface must be anodic to the equilibrium potential for the thio ion/dithiolate couple. They correlated the rest potential of a range of sulphide minerals in different thio-collector solutions with the products extracted from the surface as shown in Table 1.2 and 1.3. It can be seen from these Tables that only those minerals exhibiting rest potential in excess of the thio ion/disulphide couple formed dithiolate as a major reaction product. Those minerals which had a rest potential below this value formed the metal collector compoimds, except covellite on which dixanthogen was formed even though the measured rest potential was below the reversible potential. Allison et al. (1972) attributed the behavior to the decomposition of cupric xanthate. 

Table 1 Thermodynamics Data for the hydrogen-oxygen fuel cell...

Manes and Manes-Pozzi have suggested a cluster of the type (Vq 2 Me ), which has been taken as the basis species for a statistical treatment aimed at the interpretation of the thermodynamic data on (Ui yPUy)02 x and Pu02 x. This cluster has later been called by Manes, Sdrensen et al. the tetrahedral defect The reason of this name lies in the fact that the local bond is supposed to occur in a coordination tetrahedron of an oxygen ion in the fluorite structure in this tetrahedron, one oxygen vacancy is formed, and the two electrons are shared with the four surrounding cations, giving rise (formally) to 2(Me ) locally bonded with the vacancy. Manes, Sorensen et al. showed that by... 

Many enzymic reactions have high negative AG° values, for example glycosyl or peptide bond hydrolysis reactions in aqueous media, oxidations with oxygen as substrate etc. Some thermodynamic data of industrially applied enzymic reactions are described by Bmns and Schulze (1962), Tewari (1990) and Biselli, Kragl and Wandrey (1995). 

Experimental thermodynamic data have been reported for dibenzo-l,4-thiazino[3,2-/ ][l,4]thiazine 166 <1997MI565> compared to the corresponding oxazinooxazine, replacement of oxygen by sulfur increases ring strain. Crystallographic data show that the nitrogen centres in 166 are /7-periplanar <1994JCM458>. 

In the paper published in Explosivstoffe, Stettbacher gives thermodynamic data for al-cohol/oxygen and alcohol/hydrogen peroxide rocket fuels, the latter haviog only 1477kcal/1eg as heat of combustion... 

From the thermodynamic data of Appendix C, show that the product of the reaction of ammonia gas with oxygen would be nitrogen, rather than nitric oxide, under standard conditions and in the absence of kinetic control by, for example, specific catalysis of NO formation by platinum. (Assume the other product to be water vapor.)... 

Table 10. Thermodynamic data for reversible oxygen binding to Co(II)PPME complexes and to myoglobin...

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