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一、烧碱溶于水的放热实验物质溶于水的放热实验,初中课本已介绍了硫酸溶于水的放热现象,为了增加学生的感性知识,可增加氢氧化钠溶于水的放热实验。在试管内加入约四分之一体积的水,用酒精灯加热至沸。试管离开火焰,水停止沸腾。稍等片刻,将颗粒状的氢氧化钠少量多次(每次加入1-2粒)地加入试管。试管内的水溶液立即自动沸腾起来,很有趣味。因为烧碱溶于水.放出大量的热量,使水溶液沸腾。由于试管内的水溶液较少,每次加氢氧化钠一、二粒,不会使溶液暴沸,不会发生其它事故。
An exothermic experiment in which the exothermic experimental substance dissolved in water in caustic soda is soluble in water has been introduced in junior high school textbooks. The exothermic phenomenon in which sulfuric acid dissolves in water has been introduced. In order to increase students’ perceptual knowledge, sodium hydroxide can be added to dissolve in water. Thermal experiment. About a quarter of the volume of water is added to the tube and heated to boiling with an alcohol lamp. The test tube leaves the flame and the water stops boiling. Wait a few moments and add particulate sodium hydroxide to the test tube a few times (1 to 2 tablets each time). The aqueous solution in the test tube immediately boils automatically and it is very interesting. Because caustic soda dissolves in water, it releases a lot of heat and causes the aqueous solution to boil. Since there are few aqueous solutions in the test tube, adding one or two sodium hydroxide each time will not cause the solution to boil, and no other accidents will occur.