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講 題化學示範實驗:化學小蝌蚪—半透膜(Chemical Tadpoles - Semipermeable Membranes)
講 者國立彰化師範大學化學系 楊水平副教授
日 期2015/02/10長 度00:04:30人 氣590 次
摘 要
Chemical Demonstrations: Multicolored Chemical Tadpoles Created by Semipermeable Membranes using Calcium Alginate. Chemicals and Materials Needed for the Demonstration: diluted hydrochloric acid, sodium alginate, calcium chloride, sodium hydroxide, m-nitrophenol, thymolphthalein, phenolphthalein, Beaker, PE pipet, transparent plastic cup, glass rod, stirrer and magnetic stirrer hot plate. Procedures for the Demonstration: 1. Preparing multicolored alkaline sodium alginate solution with indicators. First add alkaline sodium alginate solution to transparent plastic cups. Then add the phenolphthalein indicator in the first cup to make a red color. Swirl the cup to mix the indicator well. Add the m-nitrophenol indicator in the third cup to make a yellow color. Add the two indicators in the second cup to make a orange color. 2. Adding dilute HCl to multicolored alkaline sodium alginate solutions. Add dilute HCl to the sodium alginate solution until the colors just disappear. 3. Placing a large beaker on magnetic stirrer hot plate and fill akaline calciun chloride solution. Place a stirrer to alkaline calciun chloride solution. Switch on the stir of magnetic stirrer hot plate. 4. Creating multicolored chemical tadpoles. Add acidic sodium alginate solution to alkaline calucium solution in turn. Drop the solution in the first, second, third, fourth, fifth, sixth and seventh cups using an individual pipet with large-diameter, respectively. 你看過溪流湖泊裡的小蝌蚪嗎?這些小蝌蚪都是黑漆漆的!你一定沒看過住在化學系館裡的­小蝌蚪,它們卻擁有「七彩」繽紛的顏色而且還活潑「游動」喔!老師要如何使這些化學小­蝌蚪「誕生」呢?你知道這些小蝌蚪涉及什麼化學原理和概念嗎? 請按下面連結,詳見本示範實驗的示範步驟、藥品與器材、原理和概念、教學提示等。 http://case.ntu.edu.tw/hs/wordpress/?p=14818 提供者:高瞻自然科學教學資源平台,國立台灣大學科學教育發展中心 http://case.ntu.edu.tw/hs/wordpress/
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