Question

One Monday morning, Paul and his classmates were in science laboratory for their practical chemistry lesson. The students were going to work in pairs to do an experiment. Before they began, the teacher gave them this description of the different stages of the experiment.

Stage 1: Prepare the equipment: a test tube, a crucible, a Bunsen burner and tongs.

Stage 2: Weigh 5 grams of baking soda (sodium bicarbonate) and put it in a crucible.

Stage 3: Heat 10 ml of hydrochloric acid (鹽酸) in a test tube.

Stage 4: Pour the warm acid onto the baking soda and continue to heat the mixture.

Result: The acid reacts with the bicarbonate（碳酸氫鹽）to form water, carbon dioxide gas and salt. The hotter the mixture, the quicker the reaction. Continue to heat the mixture until the water evaporates, leaving the salt in the crucible.

Paul and his partner followed the instructions and set up their equipment. Paul went to the cupboard to get a bottle of hydrochloric acid. He found that there was only one bottle in the cupboard so he took that. There was no label on the bottle and Paul didn’t check with the teacher if it was the right solution.

He measured the liquid and poured it into a test tube. Using tongs to hold the test tube, he heated it over the Bunsen burner. That’s when things started to go wrong. The liquid in the test tube was not hydrochloric acid. When it was heated, it formed a thick cloud of white gas. Soon the room was full of this strong smelling white gas.

All the students started coughing and their eyes hurt. The teacher immediately opened the windows and ordered the students to leave the laboratory at once. She realized that the liquid was a crylamide (丙烯酰胺) and that it is poisonous.

Fortunately, nobody was injured in the incident. However, it taught the students and the teacher a good lesson.

1.What lesson did the incident teach the students and the teacher?

A. Never have a bottle without a label in the chemistry lab!

B. Obey your teacher’s instructions in the Chemistry lab.

C. A crylamide can’t take the place of hydrochloric acid.

D. Finding something unusual happened, you have to leave the laboratory at once.

2.What substance were the students making in the experiment?

A. Water              B. Carbon dioxide gas         C. Salt          D. Poisonous gas

3.Why did Paul make the mistake?

A. He went to the cupboard to get the bottle by himself.

B. He found that there was only one bottle in the cupboard so he took that.

C. There was no label on the bottle.

D. Paul didn’t check with the teacher that it was the right solution.

4.Why did the teacher send the students out of the classroom?

A. Because the room was full of this strong smelling white gas.

B. Because all the students started coughing and their eyes hurt.

C. Because the liquid was a crylamide and that it is poisonous.

D. Because someone was injured in the incident.

 

Answer 1

1.A

2.C

3.D

4.C

【解析】

試題分析：一天上午，Paul和同學(xué)們?cè)诳茖W(xué)實(shí)驗(yàn)室上化學(xué)實(shí)驗(yàn)課。同學(xué)們?cè)诶蠋煹闹笇?dǎo)下分組進(jìn)行實(shí)驗(yàn)。Paul誤用了一個(gè)沒(méi)有貼標(biāo)簽瓶子里的液體，結(jié)果出現(xiàn)了意外，丙烯酰胺反應(yīng)后生成了有毒的氣體。

1.crylamide，排除C；出現(xiàn)緊急情況時(shí)，要看情況的嚴(yán)重性再作出判斷，排除D。實(shí)驗(yàn)出錯(cuò)的原因是Paul用了那個(gè)沒(méi)有貼標(biāo)簽的瓶子里面的物質(zhì)，故選A。

2.The acid reacts with the bicarbonate（碳酸氫鹽）to form water, carbon dioxide gas and salt. ...leaving the salt in the crucible”可知，同學(xué)們做實(shí)驗(yàn)要得到的物質(zhì)是鹽，故選C。

3.there was only one bottle in the cupboard so he took that. There was no label on the bottle and Paul didn’t check with the teacher if it was the right solution”可知，瓶子上沒(méi)有貼標(biāo)簽，Paul沒(méi)有和老師一起檢查這個(gè)瓶子是否適合做實(shí)驗(yàn)用，故選D。

4.She realized that the liquid was a crylamide (丙烯酰胺) and that it is poisonous.”可知，老師發(fā)現(xiàn)發(fā)生反應(yīng)的是丙烯酰胺，而丙烯酰胺是有毒的，故選C。

考點(diǎn)：教育類短文閱讀