问题 填空题

( 10分) “84消毒液”与硫酸溶液反应可以制取氯气(NaClO+ NaCl+H2SO4          Na2SO+ Cl2↑+H2O)为探究氯气的性质,某同学利用此原理制氯气并设计了如下所示的实验装置

请回答:

(1)从①、②、③装置中选择合适的制气装置(A处)          (填写序号)。

(2)装置B、C中依次放的是干燥的红色布条和湿润的红色布条,实验过程中该同学发现装置B中的布条也褪色,其原因可能是                                             ,说明该装置存在明显的缺陷,请提出合理的改进的方法                     

(3)为了验证氯气的氧化性,将氯气通Na2SO3溶液中,写出氯气与Na2SO3溶液反应的离子方程式                                                                

(4)氯气通入饱和NaHCO3溶液能产生无色气体,已知酸性盐酸>碳酸>次氯酸,该实验证明氯气与水反应的生成物中含有                   

答案

(1)②

(2)产生的氯气中含有水蒸气会反应生成次氯酸,在装置A、B之间增加盛有浓硫酸的洗气瓶(或干燥装置)

(3)Cl2 + SO32—+ H2O = SO42— + 2Cl+ 2H+

(4)HCl(或盐酸)

题目分析:(1)由反应方程式可知该反应为液液加热型反应,故选择装置②

(2)Cl2与水反应后生成HClO,故能使湿润的红色布条褪色,褪色的原因是HclO具有强的氧化性,装置B中的干燥布条褪色的原因可能是产生的氯气中含有水蒸气会反应生成次氯酸。改进的方法是在装置A、B之间增加盛有浓硫酸的洗气瓶,用于吸收水蒸气。

(3)氯气与Na2SO3溶液反应,氯气作为氧化剂被还原成Cl,Na2SO3作为还原剂被氧化成Na2SO4,故反应的离子方程式为:Cl2 + SO32—+ H2O = SO42— + 2Cl+ 2H+

(4)能饱和NaHCO3溶液能产生无色气体又已知酸性盐酸>碳酸>次氯酸,由强酸制弱酸,可知氯气与水反应的生成物中含有盐酸

点评:本题通过氯气的一些化学性质,考察了气体的制备、干燥、检验等实验操作,属于简单题。做本类型题目时,应该注意需要把装置进行分析,了解每一个装置的用途,并且结合实际的化学物质来分析是否能达到实验目的。

阅读理解

     "Get your hands off me; I have been stolen, "the laptop, a portable computer, shouted. That is a new

solution to laptop computer theft: a program that lets owners give their property a voice when it has

been taken.

     The program allows users to display alerts on the missing computer's screen and even to set a

spoken message. Tracking software for stolen laptops has been on the market for some time, but this

is thought to be the first that allows owners to_give_the_thief_a_piece_of_their_mind.

     Owners must report their laptop missing by visiting a website, which sends a message to the model:

a red and yellow "lost or stolen" sign appears on its screen when it is started. Under the latest version

(版本)of the software, users can also send a spoken message.

     The message can be set to reappear every 30 seconds, no matter how many times the thief closes it.

"One customer sent a message saying, 'You are being tracked. I am right at your door.'" said Carrie

Hafeman, chief executive of the company which produces the program,   Retriever.

     In the latest version, people can add a spoken message. For example, the laptop's speaker will say

"Help, this laptop is reported lost or stolen. If you are not my owner, report me now."

     The Retriever software package, which costs $29. 95 but has a free trial period, has the functions

of many security software programs. Owners can remotely switch to an alternative password if they

fear that the thief has also got hold of the access details.

     If a thief accesses the Internet with the stolen laptop, Retriever will collect information on the Internet

service provider in use, so that the police can be alerted to its location.

     Thousands of laptops are stolen every year from homes and offices, but with the use of laptops

increasing, the number stolen while their owners are out has been rising sharply.

     Other security software allows users to erase data remotely or lock down the computer.

1. The expression "to give the thief a piece of their mind" can be understood as "________".

A. to give the thief an alert mind

B. to express the owners' anger to the thief

C. to remind the thief of this conscience

D. to make the thief give up his mind

2. Different from other security software, Retriever can ________.

A. record the stealing process

B. help recognize the lost laptop

C. lock down the computer remotely

D. send a spoken message

3. One function of the program is that it allows the owner to ________ at a distance.

A. change some access details for switching on the laptop

B. turn on the laptop by using the original password

C. operate the laptop by means of alternative password

D. erase the information kept in the stolen laptop

4. Which of the following can best summarize the main idea of the passage?

A. With no Retriever, thousands of laptops are stolen every year.

B. A new software provides a means to reduce laptop theft.

C. Retriever has helped to find thieves and lost computers.

D. A new program offers a communication platform with the thief.

判断题