请结合如图所示实验装置回答有关问题: (1)写出装置A中标号a和b的仪器名称:

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问题:

请结合如图所示实验装置回答有关问题:

(1)写出装置A中标号a和b的仪器名称:a______;b______.

(2)检查装置B的气密性的方法是:将该装置中的导气管用弹簧夹夹住,往长颈漏斗中注入水至液面高出长颈漏斗的下端管口,若能观察到______现象,即可证明装置不漏气.

(3)小强用高锰酸钾制取纯净的氧气,他应选择的发生装置是______,收集装置是______.该反应的化学方程式为______.当氧气收集满并取出集气瓶后,停止该实验的正确操作步骤是先______后______.

(4)小林用过氧化氢溶液和二氧化锰混合制取氧气,他应选择的发生装置是______.小林所用制取氧气的方法与小强相比,其优点有______(答一点)

(5)装置B可做为实验室制取二氧化碳的发生装置.但该装置的不足之处是:不能控制反应随时发生、随时停止.为能有效地控制化学反应速率,可对装置B加以改进,请你写出两种改进方案:

友情提示:你可从如图所示的用品中选取,也可自行选用其他仪器.

方案一:______;方案二:______.

(6)实验室选择气体发生装置时应考虑的因素是______,选择气体收集装置时应考虑的因素是______.

考点:实验室制取和收集气体的思路化学实验方案设计和实验现象的分析
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On an annual basis, the output of the construction sector this year is much smaller than _____ of last year

as there is a steep decline by 11.1%.[ ]

A. what

B. those

C. that

D. it

题型:填空题

短文改错      下面短文中有十处错, 每处错皆用底线标出, 请将答案填写在答题卡相应的位置上。( 每小题只填一词, 不得改变原句意思。)

I am a Grade 8 student. I just moved to

Beijing with me parents two months ago.    _________

            66

Now I am study at a new secondary school   _________

            67

in Sunshine Town. It is big than my old school.  _________

                       68

I do not know the new school very good and   _________

                                    69

I have no friends there. I do not know how   _________

                  70

to talk to my new classmate. Sometimes, I   _________

                     71

am very nervous and I can’t answer them   _________

                                     72

questions. I feel really comfortable when they  _________

                         73

talk to me. During lunchtime, I always sit

alone at the playground and read books.  _________

     74

I hope they will not come on because   _________

                          75

I feel so shy when they try to talk to me.

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罐藏原理

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目前仍未投入使用的协议是()

A.SSL

B.SET

C.SHTTP

D.TCP/IP

题型:填空题

以下属于无线电发射设备年检常规项目的是()

A.频率

B.占用带宽

C.功率

D.杂散发射

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