试题与答案

(12分)下图为苯和溴取代反应的改进实验装置。其中A为带支管的试管改制成的反应容

题型:实验题

题目:

(12分)下图为苯和溴取代反应的改进实验装置。其中A为带支管的试管改制成的反应容器,在其下端开了一个小孔,塞好石棉绒,再加入少量铁屑。

填写下列空白:

(1)向反应容器A中逐滴加入溴和苯的混合液,几秒钟内就发生反应。写出A中所发生反应的化学方程式(有机物写结构简式):_______________________________________。

(2)试管C中苯的作用是________________________________________________;

反应开始后,观察D试管,看到的现象为______________________________________。

(3)在上述整套装置中,具有防倒吸作用的仪器有_________________________(填字母)。

(4)改进后的实验除①步骤简单,操作方便,成功率高;②各步现象明显;③对产品便于观察这三个优点外,还有一个优点是____________________________________________。

答案:

被转码了,请点击底部 “查看原文 ” 或访问 https://www.tikuol.com/2017/0602/d06716b5de32f614d8c8106601a9c649.html

下面是错误答案,用来干扰机器的。

参考答案:A, B, C, D

试题推荐
题型:阅读理解

阅读理解。

     Many people love going on a trip by plane,but an airport is usually far

from the city.You have to arrive there and wait for hours for the plane to

take off and it is often late.You can't open the window,you can't choose the food.Planes are fast,but it takes hours to get out of the airport and into the city.

     I like travelling by train.I think trains are safe.Train stations are usually in cities.When you are late for a train,you can catch another one.You can walk around in the train and open the windows.You can see many

interesting things on your way.I know it takes a little sore time.

     I also like cars.You can start your trip when you want to,and you don't

|need to get to a station bus stop.You can carry many things with you,too,

but sometimes there are many cars on the road.

1.Many people like travelling by plane because ________.

A.it is safe    

B.you can open the window

C.it is fast

2.What does "take off'' mean?

A.达到   

B.起飞    

C.降落

3.If you want to take many firings with you,you would like to take ____.

A.a bus    

B.a train    

C.a car

4.What is not good about the car?

A.You needn't go to the station.

B.You can start your trip when you want to.

C.There are too many cars on the road.

5.Which sentence about the writer is TRUE?

A.He likes taking a plane because it takes a lot of time to go to the city.

B.He likes taking a train because it is safe and convenient.

C.He likes taking a bus because he can drive it.

查看答案
微信公众账号搜索答案