Open AccessThe swelling of charcoal. Part II.—Some factors controlling the expansion caused by water, benzene and pyridine vapours
Author(s) -
D. H. Bangham,
Nazim Fakhoury,
Mohamed Abbas
Publication year - 1932
Publication title -
proceedings of the royal society of london. series a, containing papers of a mathematical and physical character
Language(s) - English
Resource type - Journals
eISSN - 2053-9150
pISSN - 0950-1207
DOI - 10.1098/rspa.1932.0178
Subject(s) - chemistry , adsorption , molecule , cohesion (chemistry) , benzene , vapours , pyridine , thermodynamics , organic chemistry , physics , neuroscience , biology
The experiments described in Part I of this series led to the conclusion that the expansion which charcoal undergoes in contact with water vapour, carbon dioxide, ammonia, and sulphur dioxide is connected with the existence in the adsorbed phase of a pressure due to the free movement of the molecules in directions parallel to the interface. In a later paper it was pointed out that if the relation between the percentage linear expansion (x ) and the surface pressure (F) be assumed to take the formx =λ F, (1) whereλ is a constant, then the equation found empirically to relate the adsorption and expansion in the case of these gases reduces to an expression of the Schofield-Rideal equation of state: F (A – B) =i RT. (2) Here A stands for the area per (gram) molecule, and is equal to M∑/s ifs is the weight in grams of an adsorbate (of molecular weight M) taken up by 1 gram of charcoal the effective surface area of which is ∑; B is the “incompressible” cross-sectional area per gram molecule; andi is a constant determined by the mutual cohesion of molecules and is equal to unity when such cohesion is absent.