PCOS

With certain critical Pco/Poi ratios, structural oscillations can be observed [306]. Patterns of stationary and/or traveling waves can actually be seen by means of photoemission electron microscopy (see Ref. 313, and note Section XVIII-7B. Such behavior can be modeled mathematically (e.g.. Refs. 214, 314). 

Derive Eq. XVIII-76 and also the more complete form that would show under what conditions the reaction could become first-order in Pco-... 

Figure A3.10.25 Arrhenius plots of CO oxidation by O2 over Rli single crystals and supported Rli/Al203 at PCO = PO2 = 0.01 atm [43]. The dashed line in the figure is the predicted behaviour based on the rate constants for CO and O2 adsorption and desorption on Rli under UHV conditions.

Samples of car exhaust are collected using a 4-L glass bottle evacuated to a level of less than 2 torr. A normal calibration curve using external standards of known Pco is used to determine the Pco in the exhaust samples. 

Samples were prepared by using a vacuum manifold to fill the gas cell. After measuring the total pressure, the absorbance of the sample at 2170 cm- was measured. Results are reported as %CO (Pco/ftot)- Five exhaust samples were obtained from a 1973 coupe, yielding the following results... 

Envirocell, Pco-pwfiling of Celklose-BasedProducts, a study prepared for Courtaulds and others, Aug. 1990. 

The relationship between the gas composition, austenite carbon content, and temperature is known. For example, a gas in equiUbrium with austenite containing 0.8% C must have the partial pressure ratio / Pco ) comprised of only CO and CO2, then the sum of the partial... 

FIG. 16 Variation of the steady-state rate of production, Pcoj, with Pco in the NO + CO lattice gas model with NO desorption (rate d o = 0.5), and CO desorption at various rates (shown). The inset shows the reaction rate measured experimentally at 410 K. (From Ref. 81.)... 

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