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在一类试题中,已知条件和求解之间没有直达的路径,问题解答的关键是在其间架设必要的“桥梁”。架设解决问题的“桥梁”,包括两个方面:一是架在哪儿,二是怎样架。1.质量百分比浓度的98%的浓硫酸,用等体积的水稀释后,所得溶液的质量百分比浓度A.等于49% B:大于49%C:小于49% D:无法确定分析:质量百分比浓度和水的体积之间应该有连接的“桥梁”,这“桥梁”就是密度。
In a class of questions, there is no direct path between the known conditions and the solution. The key to solving the problem is to set up the necessary “bridges” between them. Establishing a “bridge” for solving problems includes two aspects: First, where is the frame, and second is how to frame. 1. Mass percentage concentration of 98% concentrated sulfuric acid, after dilution with an equal volume of water, the mass percentage concentration of the resulting solution is equal to 49% B: greater than 49% C: less than 49% D: cannot be determined analytically: mass percent concentration There should be a “bridge” between the water and the volume of the water. This “bridge” is the density.