HKCEE要懂画的试验装置21M.doc

? by A. Fung Diagram drawn p.1 Diagrams required to draw in HKCEE Chemistry 會考化學常要繪畫的圖 1. Electronic diagrams of ionic compounds 離子化合物的電子圖 (only outermost shell electrons are shown 只顯示最外層電子) sodium chloride 氯化鈉 NaCl lithium oxide 氧化鋰 Li2O aluminium oxide 氧化鋁 Al2O3 magnesium fluoride 氟化鎂MgF2 2. Electronic diagrams of covalent molecules 共價分子的電子圖 (only outermost shell electrons are shown 只顯示最外層電子) ammonia 氨NH3 hydrogen chloride water 水 H2O 氯化氫HCl carbon dioxide ethene 乙烯 C2H4 Tetrachloromethane 二氧化碳 CO2 四氯甲烷 CCl4 ? by A. Fung Diagram drawn p.2 Diagrams required to draw in HKCEE Chemistry 會考化學常要繪畫的圖 Heat under reflux 回流加熱： Example： Oxidation of ethanol 乙醇的氧化 CH3CH2OH CH3COOH opening 開口 water out 出水 water in condenser 冷凝器 OR 入水 reaction mixture 反應混合物 anti-bumping granules / pumice stone 防漰沸小粒 / 浮石 heat 加熱 Advantages of the set-up heating under reflux 回流加熱的好處： (1) Reflux can reduce the loss of volatile substances by the condenser. 回流加熱(裝置裡的冷凝器)可減少揮發性高物質的流失。 (2) Reflux is a safe method of heating for a long time even though the reagents are flammable. 回流加熱是一個可長時間安全地加熱的裝置，它可把易燃的反應物加熱。 (3) Reflux can increase the rate of reaction. Reaction will proceed faster. 回流加熱可增加反應速率，加快進行反應。 4. Filtration過濾： To separate insoluble solid / precipitate from its liquid mixture. 從混合液中把不溶的固體 / 沉澱分離出來 funnel 漏斗 filter paper 濾紙 residue (inso