An introduction to the study of chemistry / by Ira Remsen.

  • Ira Remsen
Date:
1890
Catalogue details

Licence: Public Domain Mark

Credit: An introduction to the study of chemistry / by Ira Remsen. Source: Wellcome Collection.

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    chemical change in it. This is the cause of the electric current which passes through the wire. As has already been stated, this wire not only conducts the electric current. Fig. 2. but also becomes heated. Here, then, we have an electric current caused by chemical change, and heat caused by the electric current. As has been said, an electric current has the power to cause changes in composition, or chemical changes. This may be well illustrated by the action of a current on water. Experiment 3.—To the ends of the copper wires con- nected with two cells of a Bunsen’s or Grove’s battery fasten small platinum plates say 25 mm. (1 inch) long by 12 mm. inch) wide. Insert these platinum electrodes into water contained in a small shallow glass vessel about 15 cm. (6 inches) wide and 7 to 8 cm. (3 inches) deep, taking care to keep them separated from each other. No ac- tion will take place, for the reason, as has been shown, that water will not conduct the current, and hence when the platinum electrodes are kept apart there really is no cur- rent. By adding to the water about one tenth its own volume of strong sulphuric acid, it acquires the power to convey the current. It will then be observed that bubbles rise from each of the platinum plates. In order to collect them we may arrange an apparatus as shown in figure 3,