题干

某化学兴趣小组同学利用图中所示装置模拟炼铁:

(1)为了避免玻璃管a在加热时可能发生爆炸,加热前应____

(2)a管中氧化铁发生反应的化学方程式为____ .

(3)B装置可用来吸收二氧化碳气体,写出该反应的化学方程式____ ;B装置____ (填“能”或“不能”)用来收集CO.

(4)若a管中氧化铁全部还原成铁,冷却后称量铁的质量比反应前氧化铁的质量减少了2.4g,则加入a管中氧化铁的质量是____ g.

上一题 下一题 0.0难度 选择题 更新时间:2018-10-18 09:39:03

答案(点此获取答案解析)

先通一会儿CO,3CO+Fe2O32Fe+3CO2,CO2+2NaOH═Na2CO3+H2O,能,8

同类题1

根据题意,选择恰当的选项填入横线中。

How to become a better runner

  This is meant for runners in high school .If you want to become a better runner, then here are several things you can do.

  Connect with your team if you are new. ____ .You can ask them for advice and hang out with them outside of practice!

  If you have a workout,don’t slack off(松懈) ever.This will never improve your performance .

____ .I know some people say they do it just to stay in shape,but if you want to stay in shape you have to work for it!

  Run 6 out of  the 7 days in a week, but don’t work out on your days off. You need to relax.

____ .It dosn’t have to be as much as you would run during practice, but you should still exercise so that you don’t get out of shape.

  If you are injured, do not run. ____ . It’s common to get shin splints(小腿酸痛), so if this happens to you ,just take a break from running. It will actually make you better once you start running.

    ____ .It allow you to form a relationship with other people like a family. If you take time to become a better runner, you will be physicaaly and mentally(精神上地) stronger.


A, It takes much of your time.

B,Running is more than a sport.

C,Running can make problems worse.

D,It is an experience that you will never forget.

E,But if you are having a long break , you should still run.

F,Remember that you are supposed to run in a running sport.

G,It helps you realize that there is more to just the sport to look forward to.

同类题2

阅读下面的文字,完成下面小题

失忆人

张铭书

    那天的事有些怪。

    上午九点左右,我从单位出来沿着一条街匆匆往前走,走到下一个路口时,不由停下步子,拿不准是继续往前走呢,还是应该拐个弯儿。我问自己,你准备去做什么呢?

    这还不是最奇怪的。最奇怪的是接下来,我连自己是谁都记不起来了。我从一块橱窗的玻璃里照见了自己,里面映着一个约莫三十岁的神情沮丧的男人。我问,这男人是谁呀?橱窗当然不会回答,于是我转过头问身边的一个行人:“喂,我是谁?”那人打量我一眼,突然撒腿就跑。我望了一眼头顶的太阳,想,难道我是突然降临到地球上的一个外星人吗?

    这时一名警察出现在我面前,先前被我吓跑的那位行人指着我对警察说:“就是他!他是个疯子!”

    警察将我带到了派出所,他们翻遍我全身的口袋,也没找出任何能证明我身份的东西。

    这时我才真正害怕起来。我意识到自己同这个社会的所有联系被割裂了,沦为世界的一个孤儿,这是一种巨大的恐怖。

    这时从旁边办公桌走过来一个年轻的警察,对着我的脸端详了好久,又让我站起来看了看身高,对其他警察说:“他可能是苏老板的儿子,一星期之前苏老板已报过案,他儿子苏威想买辆法拉利跑车,结果苏老板只买给他一辆帕萨特,苏威一生气将车砸了,然后跑得无影无踪。苏威平时有吸毒的行为,有时脑子会不太清醒。说不定就是他。”别的警察就说:“那就快给苏老板打电话吧。”

    我一听原来自己是一个如此有钱的人,不禁非常得意。

    不一会儿,苏老板的电话接通了,说,他儿子的尸体已经找到了,不必麻烦警察了。

    我的心情非常失落。

    办公室里进来一位少妇,她用轻柔动听的声音问:“听说你们这里有一位找不到家的男人是吗?我老公爱喝酒,喝多了酒就不记事儿,昨晚跑出去至今没影儿,我想是不是他?”

    警察朝我一指:“就他。自己看吧。”

    那位少妇丰腴而妩媚,娇艳欲滴。她带着一股香气朝我走过来。我高兴得眼睛放光。

    但她还没到我跟前就扭身走开了。

    我心里难过极了。惆怅万分。

    一位居委会大妈来办公室办事,看到了我,好奇地瞧了又瞧,嘴里不住嘟囔:“这个人看起来好面熟呀!上个星期,我们小区大白天招了小偷,被看车棚的老李发现了,两人扭打了一阵,老李打不过他,让他跑掉了,我听到吵嚷赶过去时,远远看了小偷一眼,和这个人非常像!”

    办公室的警察们全都警惕地盯着我,眼神儿一下全变了。一个警察掏出手铐,将我铐在椅背上,然后对居委会大妈说:“你快去叫来管车棚的老李辨认一下,看是不是小偷?”

    我吓得从椅子上瘫下来,想,哪怕是个民工也好呀,怎么偏偏是个小偷呢?实在命苦!这不是自投罗网吗?

    不大一会儿,居委会大妈和一个老头儿进来了。大妈喘着粗气,说:“老李,你看这人是不是前几天跟你打架的那个小偷?”

    老李的目光如刀子一样恶狠狠地朝我戳了过来。然而那目光碰到我后马上变得柔软起来,他笑眯眯地说:“这不是张小鱼吗?你怎么在这儿?”

    大妈:“原来你们认识呀?”

    老李:“岂止认识!我跟他爸是战友。经常到他家里喝酒,他是我看着长大的。”

    一个警察赶忙过来帮我打开手铐。

    我听到自己并非小偷,心情放松了些,但仍记不起老李这个人,望着他不住地摇头。

    老李显得比我还急,掏出手机摁了一串号码。

    打完电话,高兴地对我说:“通知你爸了,你爸说你媳妇一会儿就来接你。”

    我不由对张小鱼这个人起了兴趣,问:“张小鱼是干什么的?是个怎样的人?”

    老李:“是个办公室小职员,心眼不坏,但也没多大本事,普普通通一个人儿。”

    半小时后,进来一个几乎可以忽略性别的瘦小平淡的女人。老李说:“你媳妇接你来了。”

    我傻愣着,认不出她是谁。

    那女人很生气,突然冲上来,照着我的脸响亮地掴了一巴掌:“我让你跟我装蒜!”别看瘦小,手劲可不小。

    这一巴掌让我眼冒金星。

    等金星消散以后,我突然记起她叫王金萍,是我的老婆,同时也是一位内科医生。

    王金萍打完我后抹了几把泪,对其他人说:“他这是暂时性失忆症,可能是工作压力太大造成的。”

    我跟在王金萍后头走出派出所的时候,突然想起不知从什么书上看过的一句话说,人生从来不像臆想中那么好,也不像臆想中那么坏。我虽不是有钱人,无权无势,也没有一个漂亮的老婆,但我也不是一个小偷。这样,老天就算很照顾我了,很好。

(选自《微型小说月报》,有删改)

同类题5

阅读理解
    American country music is also known as(被称为)country Western music.It has a very long history.It comes from the folk songs of immigrants(移民)from Britain.
    Country music uses simple music and words to express everyday feelings such as loneliness,love,and sadness.That is to say,country music describes life.It talks about friends and enemies,trucks and roads,farms and crops.People in many parts of the world like country music,because everyone can understand what the music is about.
    Country Western music became popular first among cowboys(牛仔)in the American West courttryside.Cowboys had to take care of cows day and night.When they were alone with the cows,they often sang beautiful and peaceful songs to calm the animals and to overcome their own fear.They were not well—educated and so they sang about their daily life in very simpie words.They played guitars,violins,and other instruments.  In the south of America,many people added instruments from their homes,like bottles and spoons.  When cowboys visited their friends and families on holidays like Thanksgiving,they usually sang and played country Western music.
    In recent years,many musicians have made country Western music a little different from the one in the past.These changes make the songs sound even better.Today singers such as Garth Brooks, Reba McEntire,Emmylou Harris,Lyle Lovett,Eddie Rabbitt,LeAnn Rimes,Randy Travis,and a group called Alabama are singing and playing in different styles.They have brought country Western music more and more fans from all over the world.