问题 实验题

根据下列实验装置图回答(装置用代号表示):

(1)写出编号为①的仪器名称____________。

(2)实验室制氧气时,应选用的发生装置是____________;实验室制二氧化碳时,应选用的发生装置是____________;检验二氧化碳气体可选用D装置,其装置中盛放的试剂一般是______________。

(3)用锌粒和浓盐酸反应制氢气,将制出的气体通入硝酸银溶液中,有白色沉淀生成,说明氢气中含有(写化学式)______________。

(4)实验室制取氧气有以下主要操作步骤:①加热  ②把药品装入试管后固定在铁架台上  ③检查装置的气密性  ④熄灭酒精灯  ⑤用排水法收集气体      ⑥从水槽中取出导管。正确的操作顺序是(写序号)_____________。

答案

(1)试管    

(2)A  ;B  ;澄清石灰水    

(3)HCl    

(4)③②①⑤⑥④

解答题
阅读理解

阅读理解。

     Mail was usually carried west on ships that sailed around the bottom of South America and then north to

California. That could take several months.

     So, in eighteen fifty-seven, D. C. Lawmakers in Congress (国会) in Washington wanted to make it possible

to send mail all the way across the United States by land. Congress offered to help any company that would

try to deliver mail overland to the West Coast. A man named John Butterfield accepted this offer. He developed

plans for a company that would carry the mail-and passengers, too.

     Congress gave John Butterfield six hundred thousand dollars to start his company. In return, he had to

promise that the mail would travel from Saint Louis, Missouri, to San Francisco, California, in twenty-five days

or less.

     It was not possible to travel straight through because of the Rocky Mountains and the deep snow that fell

in winter. So the stagecoach (马车) would travel south from Saint Louis to El Paso, Texas, then over to

southern California, then north to San Francisco. The distance was about four thousand five hundred kilometers.

     Two hundred of these stations were built, each about thirty-two kilometers apart. The workers were to

quickly change the horses or mules whenever a stagecoach reached the station. There could be no delay. Each

stagecoach was to travel nearly two hundred kilometers a day.

     One hundred stagecoaches were built and painted red or dark green. They were the most modern coaches

that money could buy. They were designed to hold as many as nine passengers and twelve thousand pieces of

mail. The seats inside could be folded down to make beds. Passengers either slept on them or on the bags of

mail.

     The cost would be one hundred fifty dollars to travel from Saint Louis to San Francisco. If a passenger was

not going all the way, the cost was about ten cents a kilometer. The passengers had to buy their own food at

the stations. The stagecoach would stop for forty minutes, two times a day.

     The company warned passengers about the possible dangers. A poster said:"You will be traveling through

Indian country and the safety of your person cannot by granted by anyone but God."

1. What is the passage mainly about?

A. Different ways of sending mail in the United States.

B. The difficulty in sending mails across the USA by land.

C. The first stagecoaches that carried both passengers and mail.

D. The history of the first stagecoaches carrying mail to the American West.

2. The reason why Lawmakers wanted to send mail by land was that _____.

A. mail was usually carried west on ships

B. it was safer to travel to send mail by land

C. it would take less time to send mail by land

D. stagecoaches could carry passengers and mail

3. As is described in the passage, the stagecoach _____.

A. could only stop once a day

B. was modern with seats, beds and cooking equipment

C. was a closed wagon operated only by skillful drivers

D. had different horses or mules pulled all the way

4. What can we learn from the passage?

A. John Buttterfield got thousands of dollars for delivering mail in stagecoaches.

B. John Buttterfield kept his promise to deliver mail straight to the West Coast.

C. Passengers might be robbed by Indians when traveling through the West.

D. Passengers needed to pay one hundred dollars for their journey.