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【简答题】
铁矿石冶炼成铁是一个复杂的过程。炼铁的原理是利用一氧化碳与氧化铁的反应,该化学方程式为 。 (1)某钢铁厂每天需消耗5000t含氧化铁76%的赤铁矿石,该厂理论上可以日产含铁98%的生铁的质量是多少? (请写出计算过程,结果精确到0.1t) (2)某化学兴趣小组在实验室中模拟炼铁原理的实验,并对固体产物的成分进行探究。 【设计实验】用一氧化碳还原纯净的氧化铁粉末,实验装置如图,酒精灯b的作用是 。 【进行实验】该小组按上述实验设计,在一定温度下进行了实验,测得下列数据: ①反应前玻璃内盛氧化铁粉末的总质量66.0g(玻璃管的质量为60.0g)。 ②反应后玻璃内盛黑色固体的总质量m(冷却到室温称量)。 【分析与讨论】本实验中,玻璃管内固体粉末由红色全部变为黑色。小认为该黑色固体全部是铁,但小提出了质疑,于是大家提出查阅资料。 【查阅资料】 ①一氧化碳还原氧化铁的固体产物的成分与反应温度、反应时间等因素有关。 ②一氧化碳还原氧化铁的实验过程中固体产物可能有四氧化三铁、氧化亚铁、铁。 ③ 物质 性质 四氧化三铁 氧化亚铁 氧化铁 铁粉 颜色 黑色 黑色 红色 黑色 能否被磁铁吸引 能 不能 不能 能 【进一步实验和得出结论】 ①该小组同学将反应后的黑色固体研磨后,再用磁铁吸引,发现黑色固体粉末全部能被吸引,则该黑色固体粉末中不可能含有氧化铁和 。 ②该小组同学将黑色固体粉末投入硫酸铜溶液中,一段时间后无紫红色固体析出,则该黑色固体粉末为 。其实,进行如上图所示实验后,若测得反应后玻璃内盛黑色固体的总质量m为 g,也能得出这个结论。 【反思与评价】一氧化碳还原氧化铁的实验中,若要得到适当提高反应温度和延长反应时间。上图所示实验装置中,应作的一处修改是 。
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举一反三
【单选题】What’s the main idea of the passage?
A.
I have an impressive lesson that I can help my son learn grammar well.
B.
I have an impressive lesson that grammar and a good vocabulary are necessary in a student’s language learning.
C.
I have an impressive lesson that grammar can be taught to students adequately.
D.
Grammar and vocabulary are important in learning a language and they should be  adequately taught to students.
【单选题】I don't remember saying anything like that. You are purposely ______ my words to prove your point.
A.
contradicting
B.
revising
C.
distracting
D.
distorting
【简答题】“You speak very good English” The other day I heard an American say to a Chinese student of English. “You 1 very good English.” But the student answered, “ No, my English is very poor.” The foreigner ...
【简答题】What’s the student’s problem?
【单选题】What’s the difference between the two “ whoas ” in the passage?
A.
The student’s whoa shows she is very excited and satisfied with her trip, while the author’s whoa shows he is satisfied with his son’s words.
B.
The student’s whoa implies she is unable to describe her trip, while the author’s whoa implies he is very proud of his son.
C.
The student’s whoa implies her language deficiency, while the author’s whoa implies his success in teaching his son learning grammar and vocabulary adequately,
D.
The student’s whoa implies she has language deficiency, while the author’s whoa implies he has a proper way.
【单选题】【例题 •单选题】企业将持有的不带息商业汇票向银行申请贴现,支付给银行的贴现利息应记入的会计科目是( )。(2016年)
A.
财务费用
B.
管理费用
C.
投资收益
D.
营业外支出
【简答题】“You speak very good English” The other day I heard an American say to a Chinese student of English. “You 41 very good English.” But the student answered, “ No, my English is very poor.” The foreigner...
【单选题】What’s the attitude of the author towards the pharmacy student’s purpose in life?
A.
Scornful
B.
Positive
C.
Neutral
D.
Indifferent
【简答题】Listen to the passsage and answer the following questions. 1. What’s the meaning of the phrase which the speaker often hears from students: “ I’m only a 1050 ” ? ______________________________________...
【简答题】根据对话内容, 选择恰当的句子补全下列对话。(每小题1分,共5分) (Miss Yu is giving a class. Suddenly some bottles drop out of a student’s desk.) T: What’s the noise there? S: Sorry, Miss Yu . 小题1: T: ( Walking over to take a look)...
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