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A Method of Generalising the Law of Mass Action for Heterogeneous Surface Reactions

Published online by Cambridge University Press:  24 October 2008

F. Hurn Constable
Affiliation:
Fellow of St John's College

Extract

To the conditions of reaction in homogeneous systems is added yet another condition, the adsorption of the reactants on the centres of activity of the surface. The surface is treated as if it were homogeneous, reaction taking place as if those centres on which the heat of activation is smallest were alone responsible for chemical change.

The general equation is worked out in terms of the rate of bombardment, and the mean lives of the molecules on the surface. It is incidentally shown that the same areas associated with the forward reaction must inevitablycatalyse the backward reaction.

The general solution is impracticable, so the special cases of irreversible synthesis and decomposition are considered and results are obtained.

Type
Research Article
Copyright
Copyright © Cambridge Philosophical Society 1928

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References

* Wilhelmy, , Pogg. Ann., vol. 81, pp. 413, 499 (1850);Google ScholarBerthelot, and de St Gilles, Pean, Ann. Chim. Phys., vol. 65, p. 385 (1862), vol. 66, p. 5 (1862);Google ScholarHarcourt, and Esson, , Phil. Trans., vol. 156, p. 193 (1866), vol. 157, p. 117 (1867), vol. 186, p. 817 (1895).CrossRefGoogle Scholar

Cf. Études sur les Affinities Chimiques, Christiania, 1867; Journ. Prakt. Chem., vol. 19, p. 69 (1879).CrossRefGoogle Scholar

Cf. Larmor, , Proc. Lit. Phil. Soc. Manchester, vol. 52 (No. 10), p. 28 (1908).Google Scholar

* Hinshelwood, and Thompson, , Proc. Roy. Soc. A, vol. 113, p. 221 (1927);CrossRefGoogle Scholar Hinshelwood and Askey, ibid. vol. 115, p. 215 (1927).

Ibid. vol. 113, p. 230 (1927).

Ibid. p. 577 (1927).

* Kinetics of Chemical Change in Gaseous Systems, Clarendon Press, 1926.Google Scholar

Z. Anorg. Chem., vol. 88, p. 285 (1914), vol. 102, p. 149 (1918).CrossRefGoogle Scholar

Z. Physical. Chem., vol. 100, p. 68 (1922).Google Scholar

§ Taylor, , Proc. Roy. Soc. A, vol. 108, p. 105 (1925), vol. 113, p. 77 (1927), and previous paper.CrossRefGoogle Scholar

* See previous paper.Google Scholar

Constable, , Proc. Roy. Soc. A, vol. 108, p. 355 (1925).CrossRefGoogle Scholar

The reaction velocity is proportional to the product of the fractional time of occupation of the active centres by the reactants.Google Scholar

§ The mean lives of the reacting molecules on the surface, the heat of activation, and the distribution of the energy among the degrees of freedom all affect the value of L. If the reaction were produced by a collision mechanism in two dimensions no alteration would be produced in the form of the relation.Google Scholar

* See note ‡ on previous page.Google Scholar

* J. Chem. Soc., vol. 127, p. 329 (1925).Google Scholar