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化学课程中的空气组成实验,历来一直采用陈旧的方法。即用一个盛水玻璃缸,把赤磷(或白磷)放入无柄蒸发皿内,然后放在玻璃缸水面上,先用火柴燃点赤磷(或白磷),使其燃烧,再扣以玻璃钟罩;或在钟罩上将塞子拔掉,用烧红的铁丝或铜丝,通入玻璃钟罩内点燃赤磷(或白磷),使生成五氧化二磷白色烟雾状物质。在燃烧过程中,赤磷(或白磷)被氧化,在这一定体积的空气中,占五分之一的氧气,生成了五氧化二磷,因而体积减少五分之一,所以罩内压力小于外边的大气压力。氧气减少多少体积,水位即上升多少水量,以
The air composition experiment in chemistry classes has traditionally used the stale method. That is, with a water glass tank, the red phosphorus (or white phosphorus) into the handleless evaporating dish, and then placed on the surface of the glass tank, the first match with red phosphorus (or white phosphorus), make it burn, and then deduct the glass Bell or pull the plug on the bell, with a red wire or copper wire, into the glass bell jar ignition red phosphorus (or white phosphorus), so that the formation of white smoke of phosphorus pentoxide. During combustion, red phosphorus (or white phosphorus) is oxidized, accounting for one-fifth of the oxygen in this volume of air, generating phosphorus pentoxide, thus reducing the volume by one-fifth, so the pressure in the hood is less than Outside the atmospheric pressure. How much oxygen to reduce the volume, the water level that is how much water to rise