问题 选择题

下列说法正确的是(NA表示阿伏加德罗常数的值)(  )

A.1molH2O中含有H2O分子数为NA

B.22.4L氧气所含的氧原子数为NA

C.17g氨气所含的原子数为NA

D.32g氧气所含的氧原子数为NA

答案

A.1molH2O中含有的分子数为N=1mol×NA/mol=NA,故A正确;

B.由于气体存在的条件不能确定是否标准状况下,则22.4L氧气不一定为1mol,无法确定原子数目,故B错误;

C.n(NH3)=

17g
17g/mol
=1mol,1个NH3分子含有4个原子,则1molNH3含有4NA个原子,故C错误;

D.n(O2)=

32g
32g/mol
=1mol,1个O2分子含有2个原子,则1molO2含有2NA个原子,故D错误.

故选A.

阅读理解

One day in Overtown, Florida, 3.7 million dollars fell from the sky! It happened when a truck turned over. There was money everywhere! One man said, “The streets were like gold.” Some people took off their shirts and filled them with money.

Police officers went from door to door in the neighborhood. They asked people to return the money. After six hours, the total returned: zero.

No one in Overtown was surprised. Many people in this town are poor. They need the money to buy food for their children. They think that God sent the money to them.

The police say this is a serious crime. “People took thousands of dollars. It’s not their money, and they have to return it.” The police also say it’s dangerous to keep the money because everyone knows the story from the news. People have money in their pockets and their backyards, and other people will try to steal it.

So far, only one person has returned some money. He is a firefighter. He found 300,000 dollars in a bag and gave it to the police. The people of Overtown still have the rest of the money.

小题1:People filled their shirts with the money from  _______.

A.the sky

B.a truck

C.a bank

D.a shop小题2:What does the underlined word “crime” in the fourth paragraph mean in Chinese?

A.金钱

B.犯罪

C.损失

D.德行小题3:Where did people hide the money they got?

A.In their kitchens.

B.In their bedrooms.

C.In their backyards.

D.In their sitting rooms.小题4:How much money was still missing?

A.3.7 million dollars.

B.300,000 dollars.

C.3.4 million dollars.

D.700,000 dollars.小题5:Which is the best title for the passage?

A.Money from the Sky.

B.Police and Money.

C.A Truck of Money.

D.Poor People and Money.

单项选择题