@article{oai:kobe-c.repo.nii.ac.jp:00005464,
 author = {中川, 徹夫 and NAKAGAWA, Testuo},
 issue = {1},
 journal = {神戸女学院大学論集, KOBE COLLEGE STUDIES},
 month = {Jun},
 note = {溶質（成分1）と溶液（成分2）からなる二成分系溶液を溶媒で希釈しても、体積は保存されない。モル濃度（物質量濃度）はある成分の物質量と溶液の体積の比で表される。それゆえ、溶液を希釈して正確なモル濃度を算出するには、体積の非加成性を考慮しなければならない。しかし、高校化学の教科書には、体積の加成性の成立を前提とした見かけのモル濃度が登場する。厳密には見かけのモル濃度は溶液と溶媒の密度が同一の場合にのみ有用である。本研究では希釈後の溶液の正確なモル濃度の算出方法を提案した。そして、この方法を、14.000mol/L および 5.000mol/L の水酸化ナトリウム（NaOH）水溶液の希釈に適用して、希釈後の正確な濃度および見かけの濃度を算出した。その結果、両者の間に不一致が認められ、特に14.000mol/L のNaOH水溶液を希釈する際、溶液と溶媒の体積比が1.000mL:0.500mLの場合に、モル濃度とみかけのモル濃度との間に約3％の相違が認められた。本方法を用いれば、希釈後の水溶液のモル濃度を容易に推算することが可能であり、高校化学の教材として有用である。, When a binary solution, which is composed of a solute (component 1) and solvent (component 2) is diluted with its solvent, is not conserved. Molarity (Amount concentration) is the ratio of the chemical amount of a component to the total volume of the solution, and therefore, the nonadditivity of volumes should be considered in order to obtain the accurate molarity of a diluted solution. However, the apparent molarity of a  diluted solution computed under the assumption that the additivity of volumes lolds appears in some Japanese high school chemistry textbooks. Strictly, the apparent molarity is only valid if the density of an original solution is equal to that of an added solvent. In this paper, the method of estimating the accurate molarity of a diluted binary solution is first derived. Secondly, this method is applied to diluting sodium hydroxide (NaOH) aqueous solutions, and  the accurate and apparent molarities of the diluted NaOH aqueous solution are estimated from the concentrated 14.000 and 5.000 mol/L aqueous ones. There is a discrepancy between the accurate and apparent molarities, and this is most significant (ca.3%) when the volume ratio of the 14.000 mol/L NaOH aqueous solution to water is 1.000 mL:0.500 mL. Using this method, it is easy to estimate the accurate molarities of the diluted aqueous solution and improve the teaching material for high school chemistry.},
 pages = {51--62},
 title = {二成分系水溶液の希釈後のモル濃度に関する考察―推算方法の誘導と水酸化ナトリウム水溶液への適用―},
 volume = {64},
 year = {2017},
 yomi = {ナカガワ, テツオ}
}