Abstract
The object of this study is the development and/or application of teaching materials to support integrated study from the standpoint of natural science.A trial gas-buret was used for volumetric analysis of carbon dioxide formed as a reaction product of sodium carbonate and a large excess of hydrochloric acid.From the results of this teaching material, the following three evidences were confirmed;(1)The volume of carbon dioxide is strictly proportional to the weight of sodium carbonate, and a calibration curve on each compound is easily obtained.(2)Molecular weight of sodium carbonate(105.0)obtained from a slope of a calibration curve is in fair agreement with that of the calculated value(105.99).(3)In six kinds of weak alescent synthetic detergents and four kinds of soaps, the content of sodium carbonate were determined.In detergents, the content of sodium carbonate were shown to be in the range of 8.16-39.3 Wt%, while in soaps it was in the range of 2.15-33.3 Wt%.That is to say, the ratio of surfactants/carbonate in these samples were not constant.It may be concluded that a trial gas-buret could be used, as teaching material, not only for acquiring of basic knowlege but also for creating and improving applications in daily life.
