Chemistry : general, medical, and pharmaceutical including the chemistry of the ; a manual on the general principles of the science, and their applications in medicine and pharmacy . unite to form gaseous water (at the sametemperature) is from three to two. This subject will again betreated of in connection with those of Chemical Combination andSpecific Gravity of Gases. 46 GENERAL PRINCIPLES OF Further Remarks ox General Chemical Notation. We may now take an experiment already made as an additionalexample of chemical action, and describe the simplest way of express-ing the sa
Chemistry : general, medical, and pharmaceutical including the chemistry of the ; a manual on the general principles of the science, and their applications in medicine and pharmacy . unite to form gaseous water (at the sametemperature) is from three to two. This subject will again betreated of in connection with those of Chemical Combination andSpecific Gravity of Gases. 46 GENERAL PRINCIPLES OF Further Remarks ox General Chemical Notation. We may now take an experiment already made as an additionalexample of chemical action, and describe the simplest way of express-ing the same by notation. When two volumes of hydrogen and oneof oxygen were caused to combine, the production of flame and noiseproved that chemical action of some kind had taken place ; had theexperiment been performed in dry vessels, evidence of the preciseaction would have been found in thebedewment or moisture producedby the condensation of the water on the sides of the tube. Similarevidence was afforded on holding a cool glass surface over the hvdro-gen-flame. The action is expressed in the following equation :— 2H2 + 02 = 2H20. Instead of an equation, the following diagram maybe employed :—. The foregoing aggregation of symbols or short-hand characters, orformula, H20, is, then, a convenient picture of the facts that havealready come before us, viz., that water is formed of the elementshydrogen, H, and oxygen, O ; moreover, that it is formed of twomeasures or volumes of hydrogen, H2, to one of oxygen, O ; and,thirdly, that the molecule of water (H20) is formed of two atoms ofhydrogen (H2) and one of oxygen (O). The formula also fulfils thefourth function of indicating that the two vokfmes of hydrogen andone of oxygen in combining condensed to two volumes of the resulting bulk of steam afterwards shrunk most considerablyin condensing to water is another matter altogether, a physical andnot a chemical result, and due to the approximation of the moleculesof water after
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