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在高中化学关于肥皂去污原理的教学过程中,组织学生进行一次用肥皂制备防水粉的实验,对于激发学生学习兴趣,发展创造性思维颇有好处,不妨一试。 一、实验原理 肥皂是一种表面活性剂,主要成分是各种高级脂肪酸钠。脂肪酸钠分子由憎水基(—R)和亲水基(—COONa)两部分组成,因此对油和水都具有亲和性。当脂肪酸钠和氢氧化钙粉末在水溶液中反应时,氢氧化钙粉末表面就会有大量脂肪酸钙生成,而脂肪酸钙分子在水溶液中几乎不能离解,因此性质发生显著
In the teaching process of high school chemistry on the principle of soap decontamination, organize students to conduct an experiment of preparing waterproof powder with soap, which is good for stimulating students’ interest in learning and developing creative thinking. First, the experimental principle Soap is a surfactant, the main ingredient is a variety of high fatty acid sodium. The fatty acid sodium molecule consists of a hydrophobic group (-R) and a hydrophilic group (-COONa) and thus has an affinity for both oil and water. When fatty acid sodium and calcium hydroxide powder are reacted in an aqueous solution, a large amount of fatty acid calcium is generated on the surface of the calcium hydroxide powder, and the fatty acid calcium molecule is hardly dissociated in the aqueous solution, and thus the properties are significantly changed.