问题 填空题

近年来出现的厄尔尼诺现象与大气中的二氧化碳含量的增多有关,请回答以下问题:

(1)空气中二氧化碳的主要来源是______;

(2)绿色植物消耗二氧化碳的过程是______作用,其生成物之一为葡萄糖(C6H12O6),写出该反应的化学方程式:______;

(3)科学研究表明,在-定条件下可通过下述反应,将工业尾气中的CO2转化为一种重要的化工原料X:CO2+4H2

 一定条件 
.
 
X+2H2O,则x的化学式为______.

(4)有人说可以利用石灰石生产出的熟石灰吸收二氧化碳,以缓减温室效应,你同意他的观点吗?______(填“同意”或“不同意”)你的理由是______.

答案

(1)空气中二氧化碳的主要来源是含碳物质的燃烧;

(2)绿色植物消耗二氧化碳的过程是光合作用,反应的化学方程式:6CO2+6H2O

 光照 
.
 
C6H12O6+6O2

(3)由质量守恒定律反应前后原子的种类和数目不变可知,在反应CO2+4H2

 一定条件 
.
 
X+2H2O中,反应前只有1个C原子,所以反应后也只能有1个C原子,即X中C原子的个数为1个;化学方程式中左右两边氧原子个数相等,所以X中不含氧原子;反应前只有8个H原子,反应后也必须有8个H原子,而2个水分子中只含有4个氢原子,所以X中H原子的个数为4个;由于X前面的化学计量数为1,故X的化学式为CH4

(4)由利用石灰石生产熟石灰的过程和熟石灰吸收二氧化碳的过程可知,熟石灰吸收的二氧化碳与利用石灰石生产熟石灰的过程产生了二氧化碳一样多,不能减缓温室效应.

故答为:(1)含碳物质的燃烧;(2)光合,6CO2+6H2O

 光照 
.
 
C6H12O6+6O2;(3)CH4;(4)不同意,熟石灰吸收的二氧化碳与利用石灰石生产熟石灰的过程产生了二氧化碳一样多,不能减缓温室效应.

单项选择题
阅读理解

阅读理解。

     Everybody hates it, but everybody does it. A recent report said that 40%of Americans hate tipping. In

America alone, tipping is a $16 billion-a-year industry. Consumers acting politely ought not to pay more than

they have to for a given service. Tips should not exist. So why do they? The common opinion in the past was

that tips both rewarded the efforts of good service and reduced uncomfortable feelings of inequality. And also,

tipping makes for closer relations. It went without saying that the better the service, the bigger the tip.

     But according to a new research from Cornell University, tips no longer serve any useful function. The

paper analyzes numbers they got from 2,547 groups dining at 20 different restaurants. The connection between

larger tips and better service was very weak. Only a tiny part of the size of the tip had anything to do with the

quality of service.

     Tipping is better explained, by culture than by the money people spend. In America, the custom came into

being a long time ago. It is regarded as part of the accepted cost of a service. In New York restaurants, failing

to tip at least l5% could well mean dissatisfaction from the customers. Hairdressers can expect to get l5%-20%, and the man who delivers your fast food $2. In Europe, tipping is less common. In many restaurants the

amount of tip is decided by a standard service charge. In many Asian countries, tipping has never really caught

on at all. Only a few have really taken to tipping.

     According to Michael Lynn, the Cornell papers' author, countries in which people are more social or

outgoing tend to tip more. Tipping may reduce anxiety about being served by strangers. And Mr. Lynn says,

"In America, where people are expressive and eager to mix up with others, tipping is about social approval. If

you tip badly, people think less of you. Tipping well is a chance to show off."

1. This passage is mainly about ________.

A. different kinds of tipping in different countries

B. the relationship between tipping and custom

C. the origin and present meaning of tipping

D. most American people hate tipping

2. Which of the following best explains the underlined phrase "caught on"?

A. become popular.

B. been hated.

C. been stopped.

D. been permitted

3. Among the following situations, in your opinion, who is likely to tip most?

A. A Frenchman just quarreled with the barber who did his hair badly in New York.

B. An American just had a wonderful dinner in a well known restaurant in New York.

C. A Japanese businessman asked for a pizza delivery from a Pizza Hut in New York.

D. A Chinese student enjoyed his meal in a famous fast food restaurant in New York.

4. We can infer from this passage that ________.

A. tipping is no longer a good way to satisfy some customers themselves

B. tipping is especially popular in New York

C. tipping in America can make service better now

D. tipping has something to do with people's character