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    精英家教网 > 初中英语 > 题目详情
    精英家教网2008年北京奥运会主体育场因外形像“鸟巢”（The Bird Nest）而得名，有一种叫五硼烷的物质结构也好似鸟巢，其化学式为B5H9．下列有关五硼烷的说法错误的是（　　）
    A、五硼烷属于化合物B、五硼烷的相对分子质量为64gC、五硼烷中硼元素和氢元素的质量比为55：9D、1个五硼烷分子由5个硼原子和9个氢原子构成
    分析：A、由不同种元素组成的纯净物是化合物．
    B、根据相对分子质量为构成分子的各原子的相对原子质量之和，进行分析判断．
    C、根据化合物中各元素质量比=各原子的相对原子质量×原子个数之比，进行分析判断．
    D、根据五硼烷分子的构成进行分析判断．
    解答：解：A、五硼烷是由硼元素、氢元素两种元素组成的纯净物，属于化合物，故选项说法正确．
    B、五硼烷的相对分子质量是11×5+1×9=64，不是64g，故选项说法错误．
    C、五硼烷中硼元素和氢元素的质量比为（11×5）：（1×9）=55：9，故选项说法正确．
    D、由五硼烷的化学式可知，一个五硼烷分子是由5个硼原子和9个氢原子构成的，故选项说法正确．
    故选：B．
    点评：本题难度不大，考查同学们结合新信息、灵活运用化学式的含义与有关计算进行分析问题、解决问题的能力．
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