2013年4月20日，四川省雅安市芦山县发生了7.0级大地震．为防止灾

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问题填空题

2013年4月20日，四川省雅安市芦山县发生了7.0级大地震．为防止灾后疫情发生，防疫人员使用了多种消毒剂进行环境消毒，其中亚氯酸钠（NaClO₂）是一种重要的消毒剂．试计算：

（1）亚氯酸钠的相对分子质量为______．

（2）亚氯酸钠中氧元素的质量分数为______．

（3）若要配制质量分数为15%的亚氯酸钠溶液200kg用于环境消毒，则需要亚氯酸钠多少kg？

答案

（1）亚氯酸钠的相对分子质量为23+35.5+16×2=90.5．

（2）亚氯酸钠中氧元素的质量分数为

16×2

90.5

×100%≈35.4%．

（3）配制质量分数为15%的亚氯酸钠溶液200kg用于环境消毒，则需要亚氯酸钠的质量为200kg×15%=30kg．

故答案为：（1）90.5；（2）35.4%；（3）30．

选择题

在短周期元素中，原子最外电子层只有1个或2个电子的元素是（）

A．金属元素

B．非金属元素

C．稀有气体元素

D．无法确定为哪一类元素

阅读理解

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