问题 问答题

某校“酸雨”(pH<5.6)测量小组的同学,取刚降落的雨水的水样,用pH计(测pH的仪器)每隔五分钟测一次pH,其数据下表:

测定时刻5:055:105:155:205:255:305:35
pH4.954.944.944.884.864.854.85
(1)根据所学的有关知识,推测“正常雨水”的pH______(填“>”,“<”或“=”).引起这种pH的原因是______.

(2)根据以上数据,判断所降雨水是否为“酸雨”?______(填“是”或“否”).

(3)经调查,这一地区有一个硫酸厂(生产过程中产生SO2)和一个电镀厂,这些厂使用的燃料主要是煤.试分析造成这一地区酸雨的主要原因是______.

其治理措施是利用水能、核能和太阳能等,或将工厂产生的废气通入______中.

答案

(1)因为空气中含有二氧化碳,二氧化碳溶于水后生成碳酸,碳酸显酸性从而使雨水的PH小于7.故答案为:<;空气中有CO2,雨水溶解CO2,形成碳酸.

(2)当溶液的PH<5.6时称为酸雨.由表中数据可知,雨水是酸雨.故答案为:是.

(3)造成这一地区酸雨的主要原因是硫酸厂产生的二氧化硫和煤燃烧生成的二氧化硫溶于水形成酸雨.由于二氧化硫能与碱溶液反应,故可以采取用碱溶液吸收的方法.

故答案为:硫酸厂产生的二氧化硫和煤燃烧生成的二氧化硫溶于水形成酸雨;碱溶液.

选择题
阅读理解

American is a mobile society. Friendships between Americans can be close and real, yet disappear soon if situations change. Neither side feels hurt by this. Both may exchange Christmas greetings for a year or two, perhaps a few letters for a while—then no more. If the same two people meet again by chance, even years later, they pick up the friendship. This can be quite difficult for us Chinese to understand, because friendships between us flower more slowly but then may become lifelong feelings, extending (延伸) sometimes deeply into both families.

Americans are ready to receive us foreigners at their homes, share their holidays, and their home life. They will enjoy welcoming us and be pleased if we accept their hospitality (好客) easily.

Another difficult point for us Chinese to understand Americans is that although they include us warmly in their personal everyday lives, they don’t show their politeness to us if it requires a great deal of time. This is usually the opposite of the practice in our country where we may be generous with our time.Sometimes , we, as hosts, will appear at airports even in the middle of the night to meet a friend. We may take days off to act as guides to our foreign friends. The Americans, however, express their welcome usually at homes, but truly can not manage the time to do a great deal with a visitor outside their daily routine (常规). They will probably expect us to get ourselves from the airport to our own hotel by bus. And they expect that we will phone them from there. Once we arrive at their homes, the welcome will be full, warm and real. We will find ourselves treated hospitably.

For the Americans, it is often considered more friendly to invite a friend to their homes than to go to restaurants, except for purely business matters. So accept their hospitality at home!

小题1:The writer of this passage must be ____.

A.an American

B. a Chinese

C.a professor

D.a student小题2: Which of the following statements is TRUE according to the passage?

A.Friendships between Americans usually extend deeply into their family.

B.Friendships between Americans usually last for all their lives.

C.Americans always show their warmth even if they are very busy.

D.Americans will continue their friendships again even after a long break.小题3: From the last two paragraphs we can learn that when we arrive in America to visit an American friends, we will probably be ___.

A.warmly welcomed at the airport

B.offered a ride to his home

C.treated hospitably at his home

D.treated to dinner in a restaurant小题4:From the underlined sentence, we can know the Chinese people  ____.

A.are strict with time

B.don’t take time seriously

C.don’t know how to use time

D.are willing to spend time for friends小题5:A suitable title for this passage would probably be “____”

A.Friendships between Chinese

B.Friendships between Americans

C.Americans’ hospitality

D.Americans’ and Chinese’s views of friendship