题目

将铁、铝、硅的混合物分为等质量的两份，一份跟足量的NaOH溶液反应，另一份跟足量稀H2SO4反应，最终产生的H2一样多，则铁与硅物质的量之比为（    ） A．2∶1         B．4∶1        C．1∶1          D．3∶1 答案：A。设每份混合物中含Fe、Al、Si的物质的量分别为x、y、z，列如下关系式： 与NaOH反应：Al ～ H2    Si～2H2                1          1   2                y    y     z   2z 与HCl反应：Al ～ H2    Fe ～ H2              1           1     1              y    y   句型转换1.The boy with a special mask is my brother.(对画线部分提问)________ ________ is your brother?2.The girl is wearing a white blouse.(改为同义句)The girl ________ ________ a white blouse.3.The girl usually has milk and cakes for breakfast.(对画线部分提问)________ ________ the girl usually ________ for breakfast?4.You look so cool in the pair of jeans.(改为同义句)The pair of jeans ________ so cool ________ you.5.Millie seldom eats fish.(对画线部分提问)________ ________ ________ Millie ________fish?6.It's a wonderful story.(改为感叹句)________ ________ ________ story it is!7.My mother buys me some moon cakes.(改为同义句)My mother ________ ________ moon cakes ________ ________。