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根据化学反应前后各元素的质量守恒来列式计算,就是元素质量守恒法。用元素质量守恒法解一类化学计算题,能化繁为简,得到事半功倍的效果。 例1 在空气中加热一定质量的Cu和Cu(OH)_2的混合物,完全反应后,残留固体的质量与原混合物的质量相等。求原混合物中Cu元素的质量分数。 解:设原混合物的质量为m克,其中Cu元素的质量分数为x％。则原混合物中Cu元素的质量为mx％克。
According to the conservation of mass of each element before and after the chemical reaction, it is the conservation of the elemental mass. Using the elemental conservation method to solve a class of chemical calculation problems, it can simplify and simplify, and get a multiplier effect. Example 1 A mixture of Cu and Cu(OH) 2 in a certain amount of mass was heated in air. After complete reaction, the mass of the residual solid was equal to that of the original mixture. Find the mass fraction of Cu in the original mixture. Solution: Let the mass of the original mixture be mg, where the mass fraction of Cu is x%. The mass of Cu in the original mixture is mx% gram.