The elements of colloidal chemistry / by Herbert Freundlich, translated by George Barger.

  • Herbert Freundlich
Date:
[1925?]
Catalogue details

Licence: Public Domain Mark

Credit: The elements of colloidal chemistry / by Herbert Freundlich, translated by George Barger. Source: Wellcome Collection.

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    of 33 quadrillion molecules, there are many more molecules in a litre of water than litres in the ocean. If we poured a litre of water into the sea, and after complete mixing took another litre of water out, the second litre would still contain 25,000 of the original molecules which we had poured away. Van’t Hoff made a great advance by showing that a substance is present in dilute solution in a condition similar to that of gases. In aqueous solution sugar is therefore divided up into single molecules which move about the liquid without any regularity, and almost independently of one another, like the mole¬ cules of a gas. The only difference is, that the sugar molecules are separated from one another by water molecules, whilst a vacuum separates the molecules of a gas. We must at once emphasize that the molecules of a dissolved substance, the solution mole¬ cules, do not necessarily consist of single molecules of the dissolved substance only ; thus in the case of sugar each sugar molecule certainly binds a number (at present unknown) of water molecules. The molecules consist of atoms, the smallest part¬ icles into which a chemical element can be subdivided. There are therefore as many kinds of atoms as there are chemical elements. But not even the atoms them¬ selves are uniformly filled by matter, they too have a definite build. Among the various theories of atomic structure, put forward during recent years, that developed by Rutherford and Bohr has met with special success, for it has been of the greatest assist-
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