Equilibrium partial pressure, calculation

This is a 4 2 reaction, and is thus pressure dependent. However, it is necessary to compute the equilibrium partial pressure of some alternative gaseous species, such as SiCls, and other hydrocarbons such as C2H2 and for this a Gibbs energy minimization calculation should be made. 

Numerical values of equilibrium constants can be calculated if the partial pressures of products and reactants at equilibrium are known. Sometimes you will be given equilibrium partial pressures directly (Example 12.3). At other times you will be given the original partial pressures and the equilibrium partial pressure of one species (Example 12.4). In that case, the calculation of K is a bit more difficult, because you have to calculate the equilibrium partial pressures of all the species. 

In air, the partial pressures of N2 and 02 are about 0.78 and 0.21 atm, respectively. The expression for K can be used to calculate the equilibrium partial pressure of NO under these conditions ... 

Having found x, refer back to the table and calculate the equilibrium partial pressures of all species. 

Calculate the equilibrium partial pressure of hydrogen if the equilibrium partial pressures of ammonia and nitrogen are 0.015 atm and 1.2 atm, respectively. 

K = 6.8 X 105. Calculate the new equilibrium partial pressures if half the NH3 is removed from the container and equilibrium is reestablished. 

Then we calculate equilibrium partial pressures, organizing our calculation around the balanced chemical equation. We see that the equilibrium constant is not very large, meaning that we must solve the equation exactly (or by using successive approximations). 

Combining the calculated value of Cg with the ideal gas equation gives the expression for Peg, the equilibrium partial pressure of sorbate vapor. 

Fig. 5. Several metals have been shown to be volatilized by carbon monoxide. A map of the safe (no metal loss) operating conditions ( ) and unsafe ( ) operating conditions for Ni/Al2Oj catalysts. The equilibrium curves for various equilibrium partial pressures of Ni(CO)4 were calculated by using thermodynamic data from the literature (72).

Worked Examples 13.9 and 13.10. The same approach can be used to calculate equilibrium partial pressures from initial partial pressures and Kp, as shown in Worked Example 13.11. 

Step 4. Calculate the equilibrium partial pressures from the calculated value of x ... 

The gas phase does not contain any other species and is maintained at latm of the total pressure. Calculate the equilibrium partial pressure of H20(g). The following data are given ... 

Calculate the equilibrium partial pressure of N02 at 1 atm total pressure. 

All the partial pressures calculated from the equilibrium constants assume unit activity for the condensed-phase components. This assumption is good when they are solid. Above the melting points of the salts, however, continued decomposition of the salt will result in a solution containing dissolved oxide and the partial pressures will depend on the melt composition, and will therefore change as the decomposition proceeds. Because of the form of Kt, the partial pressure calculation will be worst for small oxide concentrations. An examination of the various tables shows that 02 and NO are the major products of nitrate decomposition, the concentration of N02 being rather minor. This results from the fact that the equilibrium 2 N02 = 2 NO + 02 lies to the right for low pressures. 

Hydrochemical analyses should be as complete and correct as possible because they are the basic prerequisite of a reliable hydrogeochemical model. They represent the essential information and errors propagate from them to the final result. Fig. 32 to Fig. 34 show an example of the saturation index calculation for calcite and dolomite, of the C02 equilibrium partial pressure, and of the consequences an incomplete analysis may have. The following analysis is given (pH = 7.4, temp. = 8.1°C, conductivity = 418 pS/crn, concentrations in mg/L) ... 

Add each error to the corresponding assumed partial pressure to obtain a good approximation of the equilibrium partial pressure. The other five partial pressures are calculated with the equations used in step 2. 

Depending on the contacting pattern (cocurrent or countercurrent) the equilibrium partial pressure Pf will depend on the surface temperature, which depends on the heat transfer at each location in the column. For the constant rate period, the surface temperature is a constant and the integrand needed to calculate Nqq is greatly simplified ... 

Calculate the equilibrium partial pressures of S02, 02, and S03 produced from an initial mixture in which Pso2 = Po2 - 0.50 atm and PSO = 0. 

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