题目

The reason why he was sentto the hospital was he was ill. (用适当的词填空) 答案：【1】that将一块锌铜合金投入74.2g稀H2SO4中，恰好完全反应，生成氢气0.2g．求：（1）反应后所得溶液的溶质质量分数；（2）实验室现有98%的浓硫酸20g，需要多少克水才能配制成19.6%的稀硫酸？