Mole fraction of gases

Dry air near sea level has the following composition by volume N2, 78.08 percent O2, 20.94 percent Ar, 0.93 percent CO2, 0.05 percent. The atmospheric pressure is 1.00 atm. Calculate (a) the partial pressure of each gas in atm and (b) the concentration of each gas in moles per liter at 0°C. Hint Since volume is proportional to the number of moles present, mole fractions of gases can be expressed as ratios of volumes at the same temperature and pressure.)... 

Show that in terms of mole fractions of gases and total gas pressure the equilibrium constant expression for... 

We define Fj to be the mole fraction of component 1 in the vapor phase and fi to be its mole fraction in the liquid solution. Here pj and p2 are the vapor pressures of components 1 and 2 in equihbrium with an ideal solution and Pi° and p2° are the vapor pressures of the two pure liquids. By Dalton s law, Plot Pi P2 Pi/Ptot these are ideal gases and p is propor-... 

Henry s Law. This is an empirical formulation that describes equilibrium solubilities of noncondensable gases in a liquid when Raoult s law fails. It states that the mole fraction of a gas (solute i) dissolved in a liquid (solvent) is proportional to the partial pressure of the gas above the liquid surface at given temperature. That is,... 

The Henry s law constant for the solubility of radon in water at 30°C is 9.57 X 10-6 Mlmm Hg. Radon is present with other gases in a sample taken from an aquifer at 30°C. Radon has a mole fraction of 2.7 X 10-6 in the gaseous mixture. The gaseous mixture is shaken with water at a total pressure of 28 atm. Calculate the concentration of radon in the water. Express your answers using the following concentration units. 

For slightly soluble gases, H is defined as a large value (4.2 X 104 bar mol-1 that is the mole fraction of oxygen in H20). The liquid phase controls, kL = Kv For the oxygen transfer rate, the interface area is important. For oxygen bubbles, the surface area of bubbles is defined as ... 

STRATEGY To use Eq. 14, we need the total pressure (given) and the mole fraction of each component. The first step is to calculate the amount (in moles) of each gas present and the total amount (in moles). Then calculate the mole fractions from Eq. 12. To obtain the partial pressures of the gases, multiply the total pressure by the mole fractions of the gases in the mixture (Eq. 14). 

The choices come in defining M for this mixture of gases. We might define M, for each gas separately, or we might define a mean value M = where X, is the mole fraction of... 

Figure 11. Effect of pressure on the solubility (in units of mole fraction) of adamantane in dense (supercritical) carbon dioxide, methane, and ethane gases at 333 K. Data from Ref. [35].

Table 1.1 Equilibrium composition of gas mixtures at 2300 K and 0.1 atmos pressure (mole fractions of the major gases only)...

We term the component of the total air pressure due to oxygen its partial pressure , p(02). From Dalton s law (see Section 5.6), the partial pressure of oxygen p O2) is obtained by multiplying the mole fraction of the oxygen by the overall pressure of the gases in air. 

As the molar masses of oxygen, nitrogen and argon are so similar, we can approximate the mole fractions of the gases to their percentage compositions. 

The MCFC provides a good example to illustrate the influence of the extent of reactant utilization on the electrode potential. An analysis of the gas composition at the fuel cell outlet as a function of utilization at the anode and cathode is presented in Example 10-5. The Nemst equation can be expressed in terms of the mole fraction of the gases (Xi) at the fuel cell outlet ... 

A realistic boundary condition must account for the solubility of the gas in the mucus layer. Because ambient and most experimental concentrations of pollutant gases are very low, Henry s law (y Hx) can be used to relate the gas- and liquid-phase concentrations of the pollutant gas at equilibrium. Here y is the partial pressure of the pollutant in the gas phase expressed as a mole fraction at a total pressure of 1 atm x is the mole fraction of absorbed gas in the liquid and H is the Henry s law constant. Gases with high solubilities have low H value. When experimental data for solubility in lung fluid are unavailable, the Henry s law constant for the gas in water at 37 C can be used (see Table 7-1). Gas-absorption experiments in airway models lined with water-saturated filter paper gave results for the general sites of uptake of sulfur dioxide... 

Within the frame of the present first series of experiments it was almost always oxygen which was injected into supercritical water-methane mixtures. There were several reasons for this first choice. One of these was the desire, to study rich flames and their possible products first. Often the water to methane mole fraction ratio was 0.7 to 0.3. But mixtures down to a methane mole fraction of 0.1 were also used. It was possible, however, to inject oxygen and methane simultaneously into the supercritical water and produce a flame. Not possible was the production of true premixed flames. After a retraction of the thin inner nozzle capillary of the burner (see Fig. 1 b) the two gases could be mixed just below the reaction cell, but the flame reaction proceeded from the nozzle tip in the cell back towards this mixing point immediately. 

Fig. 8.8 Mole fractions of the final combustion gases of HMX-CMDB propellants as a function of (N02)...

---