Nitrous oxide decomposition rate

Copper metal surface area was determined by nitrous oxide decomposition. A sample of catalyst (0.2 g) was reduced by heating to 563 K under a flow of 10 % H2/N2 (50 cm min"1) at a heating rate of 3 deg.min 1. The catalyst was then held at this temperature for 1 h before the gas flow was switched to helium. After 0.5 h the catalyst was cooled in to 333 K and a flow of 5 %N20/He (50 cm3mirr ) passed over the sample for 0.25 h to surface oxidise the copper. At the end of this period the flow was switched to 10 % H2/N2 (50 entitlin 1) and the sample heated at a heating rate of 3 deg.min"1. The hydrogen up-take was quantified, from this a... 

Hunter in 1905 investigated the thermal decomposition of nitrous oxide by flowing the gas through a porcelain bulb in a furnace and measuring the decomposition for different contact times no attempt was made to discover the effect of surface or to measure the effect ofa wide variation in pressure. Hunter concluded that the nitrous oxide decomposition was second order and expressed the rate coefficient as... 

Figure 9. Relationship between the amount of adsorbed nitrous oxide and the rate of decomposition at steady state on MgO at 409°C.

Find the rate equation for the thermal decomposition of nitrous oxide in... 

Experiment shows that the primary reaction in the homogeneous decomposition of nitrous oxide proceeds with stoichiometry N20 => N2 + 0.5 02 and rate equation... 

Nitrosyidisulfonic acid, reaction mechanisms, 22 129, 130 Nitrous acid, 33 103 decomposition, rate constants, 22 157 as oxidizing agent, 22 133 reaction mechanisms, 22 143-156 electrophilic nitrosations, 22 144-152 with inorganic species, 22 148, 149 nitrite oxidation by metals, 22 152-154 oxidation by halogens, 22 154, 155 in solution, 22 143, 144 reduction by metals, 22 155, 156 Nitrous oxide reductase, 40 368 Nitroxyl, reaction mechanisms, 22 138 Nitrozation, pentaamminecobalt(III) complexes, 34 181... 

Methylenedinitramine undergoes decomposition under the influence of strong acids and strong bases. At a pH of about 1.0 and 10.0, however, it is fairly stable although it decomposes readily when the pH ranges between 3 and 8, the maximum of the decomposition rate occurring at pH 5.4 (Lamberton et al. [14]). Decomposition is accompanied by the evolution of nitrous oxide and formaldehyde. 

Rice, Fryling, and Weselowski (J. Amer. Chem. Soc., 1924, 46, 2405) make all reaction rates proportional to the concentration of what they call residual molecules, which have to be formed endothermically from one of the reactants. The proportion of these increases with temperature and accounts for the increase in reaction rate. Something of this kind may be true in special cases, for example, in the formation of HBr the residual molecule would be the bromine atom. But this resolution into atoms is only the limiting case of ordinary activation, and it is difficult indeed to see what the residual molecule could be, or what tautomeric change could occur in the simple decomposition of hydrogen iodide or nitrous oxide. 

An example of a change satisfying this equation very closely is to be found in the catalytic decomposition of nitrous oxide on the surface of platinum. This reaction is retarded by the oxygen produced in the change itself, and its rate is expressed by the equation d[ N20]= k[ N20] dt l+6[OJ where [N20] = a - x, [02] = x. 

When the rate equation does not correspond stoichiometrically, the reaction is called a nonelementary reaction. Consider the thermal decomposition of nitrous oxide to nitrogen and oxygen as follows ... 

There are very few cases of reactions of zero total order, and so these equations do not have wide application. Most of the known cases involve heterogeneous reactions occurring on surfaces, such as the decomposition of nitrous oxide gas on hot platinum wire, 2N2O 2N2 + O2, and the de-e.omposition of ammonia gas on a hot platinum wire, 2NH3 N2 + 3H2. The explanation seems to be that the reaction occurs only at the surface of the catalyst, and if the surface becomes saturated at a given gas or liquid concentration, further increase in the concentration in these phases cannot further change the surface concentration and so, beyond this point, the reaction seems to proceed at a rate independent of concentration in the gas phase. 

The decomposition of nitrous oxide catalyzed by halogen atoms has been studied by Kaufman et al in the range 876-1031 °K by measuring the total pressure change with time using an oil manometer. The only products observed were N2 and O2 formation of NO is inhibited. The N2O decomposition was first order in halogen atom concentration in every case (Cl, Br, and I). The concentrations of halogen were assumed to be the equilibrium values. The overall rate follows a... 

Sometimes reactions have complex rate expressions that cannot be separated into solely temperature-dependent and concentration-dependent portions. In the decomposition of nitrous oxide over platinum,... 

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