问题 选择题

在NH3.H2O⇌NH

 +4
+OH-形成的平衡中,要使NH3•H2O的电离程度及c(OH-)都增大,可采取的措施是(  )

A.通入HCl

B.加少量NaOH固体

C.加少量氯化铵固体

D.加热

答案

A.通入氯化氢气体,氯化氢和氢氧根离子反应,促进氨水电离,但氢氧根离子浓度减小,所以不符合题意,故A错误;

B.加入少量氢氧化钠固体,氢氧化钠溶于水电离出氢氧根离子,氢氧根离子浓度增大,但抑制氨水电离,故B错误;

C.加入少量氯化铵固体,氯化铵溶于水电离出铵根离子,抑制氨水电离,使氨水电离程度和氢氧根离子浓度都减小,故C错误;

D.氨水的电离是吸热反应,升高温度促进氨水电离,且氢氧根离子浓度增大,故D正确;

故选D.

阅读理解

Read the following passage. Answer the questions according to the information given in the passage and the required words limit. Write your answers on your answer sheet.

Almost everybody in America will spend a part of his or her life behind a shopping cart(购物手推车). They will, in a lifetime, push the chrome-plated contraptions many miles. But few will know—or even think to ask—who it was that invented them.

Sylvan N. Goldman invented the shopping cart in 1937. At that time he was in the supermarket business. Every day he would see shoppers lugging(吃力地携带) groceries around in baskets they had to carry.

One day Goldman suddenly had the idea of putting baskets on wheels. The wheeled baskets would make shopping much easier for his customers, and would help to attract more business.

On June 4, 1937, Goldman’s first carts were ready for use in his market. He was terribly excited on the morning of that day as customers began arriving. He couldn’t wait to see them using his invention.

But Goldman was disappointed. Most shoppers gave the carts a long look, but hardly anybody would give them a try.

After a while, Goldman decided to ask customers why they weren’t using his carts. “Don’t you think this arm is strong enough to carry a shopping basket?” one shopper replied.

But Goldman wasn’t beaten yet. He knew his carts would be a great success if only he could persuade people to give them a try. To end this, Goldman hired a group of people to push carts around his market and pretend they were shopping! Seeing this, the real customers gradually began copying the phony(假冒的)customers.

As Goldman had hoped, the carts were soon attracting larger and larger numbers of customers to his market. But not only did more people come—those who came bought more. With larger, easier-to-handle baskets, customers unconsciously bought a greater number of items than before.

Today’s shopping carts are five times larger than Goldman’s original model. Perhaps that’s one reason Americans today spend more than five times as much money on food each year as they did before 1937—before the coming of the shopping cart.

小题1:What do the underlined words “chrome-plate contraptions” in Paragraph 1 refer to ? ( no more than 3 words)

小题2:What was the purpose of Goldman’s invention? (no more than 8 words)

小题3:Why was Goldman disappointed at first? (no more than 6 words)

小题4:Why did Goldman hire people to push carts around his market? (no more than 10 words)

判断题