问题 填空题

(3分) 如下图所示,已知物质X是一种含钠元素的化合物,其余四种物质在一定条件下都可以转化成X。试推断:

(1)物质X的化学式为          

(2)写出其中既有X且又有气体生成的反应的化学方程式                       ;

(3)图中所有生成X的化学反应的反应类型均是                  反应。

答案

(每空1分,共3分) (1) NaNO3  (2) Na2CO+ 2HNO3= 2NaNO3  + CO2↑+H2O

(3)复分解    (其他合理答案同样给分)

分析:由题目的信息可知:物质X是一种含钠元素的化合物,其余四种物质在一定条件下都可以转化成 X,因此X是硝酸钠;因为氢氧化钠与硝酸反应生成硝酸钠和水,碳酸钠和硝酸反应生成硝酸钠和水和二氧化碳,氯化钠和硝酸银溶液反应生成氯化银白色沉淀和硝 酸钠,硫酸钠和硝酸钡反应生成硫酸钡白色沉淀和硝酸钠;以上反应都是由两种化合物互相交换成分生成另外两种化合物,属于复分解反应.

解答:(1)由题目的信息可知:物质X是一种含钠元素的化合物,其余四种物质在一定条件下都可以转化成X,因此X是硝酸钠;故答案为:NaNO3  

(2)碳酸钠和硝酸反应生成硝酸钠和水和二氧化碳,配平即可,故答案为:Na2CO3+2HNO3=2NaNO3+CO2↑+H2O

(3)以上反应都是由两种化合物互相交换成分生成另外两种化合物,属于复分解反应;故答案为:复分解 (其他合理答案同样给分)

点评:本考点考查了物质的制备,物质的制备有一下几种类型:一种是只能用题目给出的原料来制取;一种是自己选取原料来制备新物质;还有的是给你一部分药品,其它自选等.本题只要结合物质的性质,灵活应用,答案就会迎刃而解.

阅读理解

One of the founding fathers of the internet has predicted the end of traditional television. Vint Serf, who helped to build the internet while working as a researcher in America, said that television was approaching its “iPod moment.”

In the same way that people now download their favorite music onto their iPods, he said that viewers would soon be downloading most of their favorite programmers onto their computers. “85 percent of all video we watch is pre-recorded, so you can set your system to download it at any time,”said Mr. Cerf, who is now the vice-president of Goggle.

“You’re still going to need live television for certain things--like news, sporting events and emergencies--but increasingly it will be almost like iPod, where you download content to look at later.”

Although television-on-demand has not yet become a main activity in the UK, the BBC, 1TV and Channel 4 have all invested a lot of money in technology which Mr. Cerf think will enable viewers to watch their favorite shows on their computers.

However, some critics(批评家)have warned that the Internet will collapse(崩溃)if millions of people try to download programmers at the same time.

Over the next four years, scientists think the number of videos watched over the Internet will double, with people moving from short chips to hour-long programmes.

Broadband companies claim that the service will cause“traffic jams”,which will cost millions of pounds to solve. Mr. Cerf dismissed these warnings, saying that critics had predicted 20 years ago that the net would collapse when people all around the world started to use it at the same time, “We’re far from exhausting (用尽)the capacity,” he said.“I want every one of the six billion people in the planet to be able to connect to the Internet.”

61.Vint Cerf is all the following EXCEPT that ___________.

A. a researcher in the United States

B. the vice-president of Goggle

C. one of the founders of the Internet

D. a manager of a broadband company

62. Which of the following is NOT something Vint Cerf has predicted?

A. Traditional television will soon have its iPod moment.

B. The number of videos watched over the Internet will double.

C. Viewers will be able to download TV programmers onto their iPods.

D. Viewers will be able to watch their favorite TV shows on the Internet.

63. According to the passage, people can always do all the following EXCEPT ____________.

A. watch short clips over the Internet

B. download live TV over the Internet

C. download per-recorded videos over the Internet

D. listen to their favorite music on their computers

64. Some critics are now predicting __________.

A. the Internet will collapse if millions of people use it at the same time

B. people all over the world will be able to connect to the Internet

C. the Internet will crash if  too many people download TV programmes at the same time

D. the videos people watch over the Internet

65. This passage mainly tells us __________.

A. a Goggle expert is predicting the end of traditional television

B. the Internet will never be used to download people's favourite shows

C. the Internet will become more popular

D. something about Vint Cerf

单项选择题