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几种能发生化学反应的物质在一起时,反应常常有先后,学生理解和掌握起来有一定的难度,在此对常见的情况略作概括和分析。一、金属与酸溶液、盐溶液发生置换反应的顺序金属单质与盐溶液中的金属元素或酸中的氢元素,在金属活动性顺序表中,距离越远越先反应。1.两种金属和一种盐都能反应时,活动性强的金属优先。金属Mg和Fe同时放入CuCl2溶液中,Mg可以从CuCl2溶液中置换出Cu生成MgCl2,Fe也可以从CuCl2溶液中置换出Cu而生成FeCl2,当把两种金属同时放入足量的CuCl2溶液中,Mg先
When several kinds of chemical reaction substances are brought together, the reaction often comes first and foremost, and the students have a certain degree of difficulty in understanding and mastering. Here, the common situation is briefly summarized and analyzed. First, the metal and acid solution, salt solution replacement reaction sequence Metal elemental and salt solution of metal elements or acid hydrogen elements in the metal activity sequence table, the longer the distance the more reaction. 1. When both metals and one salt react, highly reactive metals are preferred. The metal Mg and Fe are simultaneously put into the CuCl2 solution, Mg can be substituted from the CuCl2 solution to form MgCl2, and the Fe can also replace the Cu from the CuCl2 solution to generate FeCl2. When the two metals are simultaneously put into a sufficient amount of the CuCl2 solution In, Mg first