Chemistry : general, medical, and pharmaceutical including the chemistry of the British Pharmacopœia a manual on the general principles of the science, and their applications in medicine and pharmacy / by John Attfield.

John Attfield

Date:: 1881

Credit: Chemistry : general, medical, and pharmaceutical including the chemistry of the British Pharmacopœia a manual on the general principles of the science, and their applications in medicine and pharmacy / by John Attfield. Source: Wellcome Collection.

58/850 (page 34)

$other elements present, namely, the atoms of sulphur and oxygen of the sulphurous acid molecules, combine by prefer- ence with these atoms and form new molecules, the sulphur and hydrogen forming sulphuretted hydrogen, and the ox^'-gen and hydrogen producing water—the former escapes with the great bulk of the hydrogen, while the water remains svith. the water already in the vessel. Note.—Ordinary hydrogen gas—that is, hydrogen not in the nascent condition—will not thus attack sulphurous acid. Doubtless the amount, or extent of attraction of two atoms of hydi'ogen for one atom of, say, the sulphur in the sulphurous acid molecule, is a constant amount; but the uncombined, nascent atoms can, it is only fair to suppose, get much nearer to the attacked molecule than they can after they have themselves combined to form a molecule, molecules (but not atoms) having an appreciable amount of space between them, as will be further shown almost immediately. In other words, it is probably distance which prevents an attack which would be inevitable at close quarters. These remarks apjsly to all similar reactions of other elements. Conditions and natuee of the manifestation of the Chemical Force. The exertion of chemical afl&nity is only possible when the masses of the bodies touch. Thus it was necessary to bring the oxygen, hydrogen, phosphorus, chlorine, sulphur, carbon, iodine, and iron into ordinary contact, in the respective ex- periments with those elements, before the various reactions occurred. The exact nature of these actions, as indeed of all in which substances act chemically, would seem to be an in- terchange, most generally a mutual one, of the atoms of which the molecules consist—a change of partners, so to speak. Thus in the experiment in which hydrogen and chlorine gases united to form hydrochloric acid gas, a pair of atoms in a hydrogen molecule and a paii* of atoms in a chlorine molecule, finding themselves opposite to each other, changed places, the atoms of each of the old molecules unlinking, so to say, and pairing off in fresh couples—as two brothers who for many years have been close companions, and two sisters similarly united, thrown freshly into each other's society, soon accept new and still more congenial companionship. Hydrogen ) ■, ( Chlorine ) be- j Hydrogen ^ j J Hydrogen } Hydrogen ] \ Chlorine J come \ Chlorine ) ( Chlorine i$