论文部分内容阅读
一、现行教材中的空气中氧气含量测定的演示实验沪教版九年级化学(上册)第二章第一节:由多种物质组成的空气.在对空气成分分析时,进行了对空气中氧气含量测定的实验.该实验中,用过量的红磷放在燃烧匙中点燃,然后迅速插入集气瓶中并塞紧塞子,冷却后液面上升(如图所示).实验原理:过量的红磷消耗了装置内的空气中的氧气,生成五氧化二磷固体导致压强减小,水面上升.二、教材中实验的不足之处第一,该实验作为课堂的演示实验,最大的不足之处在
First, the existing teaching materials in the air oxygen content of the demonstration experiment Shanghai Jiuhua Chemistry (Volume) Chapter II, Section I: composed of a variety of substances in the air composition analysis, carried out in the air Oxygen content of the experiment, the experiment, the excess red phosphorus placed in the ignition key ignition, and then quickly inserted into the gas collection bottle and plug, cooling liquid level rise (as shown) .Experiment principle: excess Of the red phosphorus consumes the oxygen in the air within the device, resulting in a solid phosphorus pentoxide resulting in reduced pressure, the water surface .In two, the shortcomings of the textbook experiment First, the experiment as a classroom demonstration experiment, the biggest shortfall At