乙醇、乙二醇、甘油分别与足量金属钠作用,产生等量的氢气,则三种醇的物质的量之比为 [ ]
A.6∶3∶2
B.1∶2∶3
C.3∶2∶1
D.4∶3∶2
答案:A
短文改错(共10小题;每小题1分,满分10分)
I often dream of a teacher. I dream of standing on the platform in the classroom and give lessons to lovely boys and girls. I teach them, play with them, but watch them growing up. I am always
young when I was staying with them. I know there is not easy to be a teacher. You have to learn in
order to teach. Without enough knowledges, you can never learn well. What is more, you have to
be friends with your pupils and take good care of him. Only by this way can you be a good teacher
and win respect from them. Though I am a student now, I will work as very hard to make my
dream come true.
常温下,铁与水几乎不反应,但高温下,铁能与水蒸气反应,生成四氧化三铁(磁铁矿的主要成分)和氢气.请设计实验,证明铁粉与水蒸气能够发生反应并且产生了氢气.
(1)铁粉与水蒸气反应的化学方程式是: ________ ,该反应的基本反应类型是 ______ .
(2)某兴趣小组同学用如图所示装置进行实验(D可以重复利用),请你协助该小组同学完成以下实验:
①实验结束后,发现B中铁粉全部转化产生了黑色块状固体,为了证明黑色固体不是铁粉,该兴趣小组同学取黑色固体进行实验,请你帮他们完成下列实验报告:
②为了除去B中出来的水蒸气,该小组同学在C中首先连接了D作为洗气装置对氢气进行干燥,则D瓶中填装的药品可以是 _________ ;
③为了收集和验证所产生的氢气,该小组同学使用D作为气体的收集装置,则气体应该从 _________ (填“a”或“b”)通入.
④实验室通常用浓盐酸与二氧化锰共热的方法来制取氯气,一般可选用装置A做气体的发生装置,理由是 _________ .