著者

中川 徹夫

出版者

神戸女学院大学

雑誌

論集 (ISSN:03891658)

巻号頁・発行日

vol.59, no.2, pp.93-102, 2012-12

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When the binary solution, whichi is composed of a solute and a solvent, is diluted with its solvent, volume is not conserved; the total volume of an original solution and an added solvent is not equal to that of its diluted solution. This phenomenon is well known, however, it has been never quantitatively discussed from the viewpoint of science education. In this paper, the method of estimating the volume of a diluted binary solution is first derived. The volume of a diluted solution is obtained from volumes and densities of an original solution and an added solvent and from the density of the diluted solution. Densities of the original and diluted solutions are calculated using an empirical equation, which is a power function of the mass fraction of a solute. Successively, our method is applied to D-glucose and sucrose aqueous solutions in order to examine volume changes in diluting these solutions with water at 20℃, The concentration ranges of original D-glucose and sucrose aqueous solutions are 0-0.6000 and 0-0.8000 mass fractions of solutes respectively. The volume ratios of the original solution to the added solvent are 1.000 mL: 5.000mL, 2.000mL:4.000mL, 3.000mL:3.000mL, 4.000mL:2.000mL, and 5.000mL:1.000mL, For both aqueous solutions, volumes decrease over the 0.2500 solute mass fraction range, and they reach minimum values (5.983mL for D-glucose and 5.963mL for sucrose aqueous solution) at the ratio 3.000mL: 3.000mL. Although these volume changes are too small to be detected using our microscale experiments, the obvious volume decreases are recognized after diluting original solutions Estimating volumes of diluted aqueous solutions is very simple and easy, and it is concluded that our method is useful as teaching material for high school science.

著者

中川 徹夫

出版者

公益社団法人 日本化学会

雑誌

化学と教育 (ISSN:03862151)

巻号頁・発行日

vol.40, no.4, pp.266-267, 1992-04-20 (Released:2017-07-13)

著者

中川 徹夫

出版者

日本物理教育学会

雑誌

物理教育学会年会物理教育研究大会予稿集 32(2015) (ISSN:24330655)

巻号頁・発行日

pp.37-38, 2015-08-08 (Released:2017-07-20)

著者

中川 徹夫 Testuo NAKAGAWA

出版者

神戸女学院大学研究所

雑誌

神戸女学院大学論集 = Kobe College studies (ISSN:03891658)

巻号頁・発行日

vol.65, no.2, pp.41-50, 2018-12

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植物色素の一種であるアントシアニンは、中性では紫色を示すが、酸性では赤色~赤紫色、塩基性では青緑色~緑色~黄色とその色調を変化させるため、化学実験の酸塩基指示薬として利用できる。以前に著者は、巨峰の果皮やマロウブルーから抽出したアントシアニンを高等学校化学の教材として使用する方法について提案した。本研究では、12ウェルプレートと巨峰の果皮およびマロウブルーを用いた各種水溶液の酸性、中性、塩基性の識別に関するマイクロスケール実験教材について検討した。試薬として、0.1、0.01、0.001mol/L 塩酸 (HCl) 、0.1mol/L 酢酸 (CH₃COOH) 、0.1mol/L 塩化ナトリウム (NaCl) 、0.1mol/L ショ糖 (C₁₂H₂₂O₁₁) 、0.1、0.01、0.001 mol/L 水酸化ナトリウム (NaOH) 、0.1mol/L アンモニア (NH₃) 、飽和水酸化カルシウム (Ca(OH)₂) (石灰水) を用いた。希薄な0.001mol/L HCl と NaOH 以外は、アントシアニンの色調変化よりそれぞれの水溶液の酸性、中性、塩基性を識別できた。本教材を用いた授業実践を兵庫県下の高等学校2校で実施し、高等学校化学基礎の教材としての有用性を確認した。Anthocyanin, a plant pigment, shows purple in neutral, however, it turns red or red-purple when acidic and blue-green, green, or yellow when basic. Therefore, it can be used as an acid-base indicator in chemistry experiments. Previously, we proposed how to use them as teaching materials for high school chemistry. In this study, we have investigated teaching materials for a microscale experiment on classifying various aqueous solutions into acidic, neutral. and basic ones using a 12-well plate, kyoho peels, and mallow blue's petals. We have used various aqueous solution such as 0.1, 0.01, 0.001 mol/L hydrochloric acids (HCl), 0.1 mol/L acetic acid (CH₃COOH), 0.1mol/L sodium chloride (NaCl), 0.1mol/L sucrose (C₁₂H₂₂O₁₁), 0.1, 0.01, and 0.001 mol/L sodium hydroxides (NaOH), 0.1 mol/L ammonia (NH₃) (ammonia water), and saturated calcium hydroxide (Ca(OH)₂) (limewater). Except for 0.001 mol/L HCl and NaOH, these aqueous solutions can be correctly classified into acidic, neutral, and basic ones from the color change of anthocyanin. Using these microscale teaching materials, practical lessons have been carried out at two senior high schools in Hyogo Prefecture, and it has been found that such teaching materials are useful for high school basic chemistry.