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初中物理第二册“物态变化”部分,在介绍几种物质熔点的表格中,有一种叫“海波”的物质。在教师未作介绍之前,学生往往误认为是海水、海浪等等。“海波”究竟是什么?“海波”是英文hypo的音译,海波又称大苏打,学名叫硫代硫酸钠,是硫的含氧盐,分子式是:Na_2S_2O_2,它的物理性状是:无色透明的结晶体。易溶于水,水溶液呈现弱碱性,在中性、碱性溶液中很稳定,在酸性溶液中则迅速分解。海波是一种还原剂,它与碘作用时,被氧化为连四硫酸钠;与氯、溴等作用时被氧化为硫酸盐,因此,它可以作脱氯剂。硫代硫酸根有很强的络合能力,照相底片上
In the “change of state” section of Physics Book 2 of junior middle school, in the table introducing the melting point of several substances, there is a substance called “Haibo”. Before the teacher made a presentation, students often mistakenly thought it was seawater, waves, and so on. What is “Haipo”? “Haibo” is a transliteration of English hypo, and Haibo is also known as soda. Its scientific name is sodium thiosulfate, and it is an oxygen-containing salt of sulfur. The molecular formula is: Na_2S_2O_2, and its physical properties are: Colorless transparent crystals. Soluble in water, the aqueous solution is weakly alkaline, stable in neutral and alkaline solutions, and rapidly decomposed in acidic solutions. Haibo is a reducing agent. When it reacts with iodine, it is oxidized to sodium tetrathionate. When it reacts with chlorine and bromine, it is oxidized to sulphate. Therefore, it can be used as a dechlorinating agent. Thiosulfate has a strong complexing ability on photographic negatives