题目内容

【题目】为了验证木炭可被浓H2SO4氧化成CO2，选用如图所示仪器(内含物质)组装成实验装置：

(1)如按气流由左向右流向，连接上述装置的正确顺序是(填各接口字母)：________接________，________接________，________接________。

(2)仪器乙、丙应有怎样的实验现象才表明已检验出CO2?

乙中________________________，丙中________________________。

(3)丁中酸性KMnO4溶液的作用是__________________________________________。

(4)写出甲中反应的化学方程式____________________________________________。

【答案】(1)A F E C D B

(2)澄清石灰水变浑浊 品红溶液未褪色

(3)吸收SO2

(4)C+2H2SO4(浓)CO2↑+2SO2↑+2H2O

【解析】木炭与浓硫酸加热反应生成CO2、SO2和H2O。其中CO2、SO2在化学性质上的相同点都是酸性氧化物，都跟澄清石灰水中的Ca(OH)2反应，使澄清石灰水变浑浊，这会干扰CO2的鉴别。SO2和CO2在化学性质上的明显不同点是SO2有漂白性和强的还原性，而CO2都没有。所以，在鉴别CO2时，首先用酸性KMnO4溶液将SO2氧化除去，再用品红溶液检验是否被完全除去，最后用澄清石灰水检验CO2的存在，是一种确认CO2存在的好方案。

练习册系列答案
相关题目

【题目】小王在年初用50万元购买一辆大货车，第一年因缴纳各种费用支出6万元，从第二年起，每年都比上一年增加支出2万元，假定该车每年的运输收入均为25万元.小王在该车运输累计收入超过总支出后，考虑大货车作为二手车出售，若该车在第年年底出售，其销售价格为25-万元（国家规定大货车的报废年限为10年）.

（1）大货车运输到第几年年底，该车运输累计收入超过总支出？

（2）在第几年年底将大货车出售，能使小王获得的年平均利润最大（利润=累计收入+销售收入-总支出）？

【题目】阅读理解。

阅读下列短文，从每题所给的四个选项 （A 、B 、C 和 D ）中，选出最佳选项。

Summer Science Class registration begins on March 8! If you are interested in science，the environment，or conservation and you are in grades 7－12，sign up soon for Black Rock Forest Consortium's Summer Science Class program. You can download the Summer Science Classes 2013 brochure here. It is easy to register；just call 8455344517 or click here.

Twelve weeklong courses in the natural sciences and the arts are offered at Black Rock Forest in Cornwall from July 15 through August 9.Two more classes are offered with site partners，including “The Art of Scientific Observation，” hosted jointly by Black Rock Forest Consortium and Storm King Art Center，one of the world's leading sculpture parks，and “A Nautical Expedition” hosted jointly by the Consortium and the Constitution Marsh Audubon Center.

We are delighted to announce two special “away” classes that are part of the Summer Science Class program this year: an “Adirondack EcoAdventure” beginning August 11，and “Conservation Biology in Florida，” beginning June 23 and featuring field work on the Gulf Coast in cooperation with the University of Florida's Seahorse Key Marine Biological Laboratory. For more information on the Summer Science Class program，please read our press release.

Black Rock Forest Consortium is a nonprofit organization founded in 1989 to advance scientific understanding of the natural world through research，education and conservation programs.

【1】If you want to be a member of Summer Science Class，you should ________．

A．visit Black Rock Forest first

B．download their brochure

C．cal a phone 8455344517

D．register before March 8

【2】Summer Science Class's courses are________．

A．only about science subjects

B．cooperated by several organizations

C．from July 15 through August 9

D．hosted by the world's leading professors

【3】Where can you find the article?

A．From a web site.

B．From a traveling brochure.

C．From a novel book.

D．From one famous magazine.

【题目】阅读理解。

阅读短文，从每题所给的四个选项(A、B、C和D)中，选出最佳选项。

“BEST PRODUCT WE’VE EVER SEEN”－THIS REALLY WORKS－ON SALE NOW

Need to lower your cholesterol（胆固醉）？We strongly recommend CholestrolblockTM. This really works, and now is the best time to buy，because of a special offer for the first 250 customers only for a limited time.

* Takes cholesterol out of food，no matter what you eat.

* Clinically demonstrated effective in university and hospital testing．

* Lowers cholesterol absorption up to 42% or more．

* “NO SIDE EFFECTS unlike Liptor, Zocor，Crests＆other commonly prescribed（处方的） medications－safe and effective.

* “Outsells all other brands on Internet every month.

LIMITED TIME ONLY一Try Cholesterol Watchers free with purchase.

【1】If you happen to be the 200th customer to buy Cholesterolblock, you will .

A. be able to buy it at a low price

B. be the luckiest one online

C. try it free of charge

D. change your diet

【2】Liptor，Zocor，Crestor are ．

A. diseases B. side effects

C. medicines D. cholesterol

【3】Where can you most probably read this passage?

A. In a travel guide book．

B. On a university bulletin board（布告牌）．

C. In a health magazine.

D. In a doctor’s prescription.

【题目】短文改错

假定英语课上老师要求同桌之间交换修改作文，请你修改你同桌写的以下作文。文中共有10处语言错误，每句中最多有两处。每处错误涉及一个单词的增加、删除或修改。

增加：在缺词处加一个漏词符号(/\)，并在其下面写出该加的词。

删除：把多余的词用斜线(\)划掉。

修改：在错的词下画一横线，并在该词下面写出修改后的词。

注意：1. 每处错误及修改均仅限一词；

2. 只允许修改10处，多者(从第11处起)不计分。

What is the most valuable thing in the world? Although the answer many vary from person to person, but as for me, reading books is most valuable than anything else. As old saying goes, “To open a book is always helpful. ”

First, books are our teachers. They introduce different kind of knowledge to us, include science and literature. Books are our friends either. With the valuable experience in them, books often helps us out when we meet difficulties. By increasing our knowledge and enlarge our experience, books lead us down the road to succeed. Therefore, to read more books is the best policy for we young students.

【题目】 短文改错（共10小题；每小题l分，满分10分）

假定英语课上老师要求同桌之间交换修改作文，请你修改你同桌写的以下作文。文中共有10处语言错误，每句中最多有两处。每处错误仅涉及一个单词的增加、删除或修改。

增加：在缺词处加一个漏字符号（∧），并在其下面写出该加的词。

删除：把多余的词用斜线（＼）划掉。

修改：在错的词下划一横线，并在该词下面写出修改后的词。

注意：

1. 每处错误及其修改均仅限一词；

2. 只允许修改10处，多者（从第11处起）不计分。

Dear high school freshmen,

You were off to high school. You are now an official teenager get ready to become a young adult. Most of you will be excited in the first day. But some of you may feel concerned about which lies ahead. Surviving high school is total possible. You should join in at the least one activity before school starts. Besides, neither limit you to just the friends you already have nor afraid to ask for help. As a graduation, I’ll tell you the next three years of your life will fly by. It’s what you do during this period that count the most.

【题目】 短文改错（共10小题；每小题l分，满分10分）

假定英语课上老师要求同桌之间交换修改作文，请你修改你同桌写的以下作文。文中共有10处语言错误，每句中最多有两处。每处错误仅涉及一个单词的增加、删除或修改。

增加：在缺词处加一个漏字符号（∧），并在其下面写出该加的词。

删除：把多余的词用斜线（＼）划掉。

修改：在错的词下划一横线，并在该词下面写出修改后的词。

注意：

1. 每处错误及其修改均仅限一词；

2. 只允许修改10处，多者（从第11处起）不计分。

Today I visited the Smiths — my first visit to a American family. They live in a small quietly town. It was very kind for them to meet me at the railway station and drove me to their home. The Smiths did their best to make me feel at home. They offered myself coffee and other drinks. We have a good time talking or laughing together. They happy to know everything about China and asked me lots of question. In fact, they are planning to visit China in next year.

【题目】 短文改错（共10小题；每小题l分，满分10分）

假定英语课上老师要求同桌之间交换修改作文，请你修改你同桌写的以下作文。文中共有10处语言错误，每句中最多有两处。每处错误仅涉及一个单词的增加、删除或修改。

增加：在缺词处加一个漏字符号（∧），并在其下面写出该加的词。

删除：把多余的词用斜线（＼）划掉。

修改：在错的词下划一横线，并在该词下面写出修改后的词。

注意：

1. 每处错误及其修改均仅限一词；

2. 只允许修改10处，多者（从第11处起）不计分。

This term our school has offer more than ten optional courses with which students can choose. The courses are given from 4:00 to 5:30 every Thursday afternoon. Students show interest in optional courses. Their favorite are computers, speaking English, art and so on. They say they have learned a lot about that is not taught in textbooks and they have got a great deal of practice. Therefore, students are not quite satisfied. They hope that more optional courses will be offered or the homework will be less. They suggest more trips and visits to be organized so that they can learn more about what’s going on inside school.

【题目】如果小朋友误吞了金属类物品于腹腔内，如何把它取出来呢？某同学在学习了磁场之后，设计出了这样一个仪器，如图所示．当仪器顶部接触金属物品时，将手控环内推，再拉出整条塑料管。

（1）你能说出这种仪器的原理吗？

（2）如果小朋友不慎吞下的是易拉罐拉环或一个回形针，哪种物体可以用这种仪器取出来？

（3）如果把活动永磁铁换成电磁铁，你认为是不是更实用呢？

违法和不良信息举报电话：027-86699610 举报邮箱：58377363@163.com

精英家教网