问题 选择题

570÷80=[ ]

A.7…1

B.70…1

C.7…10

答案

答案:C

实验题

(13分)乙酸异戊酯是组成蜜蜂信息素质的成分之一,具有香蕉的香味,实验室制备乙酸异戊酯的反应装置示意图和有关数据如下:

实验步骤:

在A中加入4.4 g的异戊醇,6.0 g的乙酸、数滴浓硫酸和2~3片碎瓷片,开始缓慢加热A,回流50分钟,反应液冷至室温后,倒入分液漏斗中,分别用少量水,饱和碳酸氢钠溶液和水洗涤,分出的产物加入少量无水硫酸镁固体,静置片刻,过滤除去硫酸镁固体,,进行蒸馏纯化,收集140~143 ℃馏分,得乙酸异戊酯3.9 g。回答下列问题:

(1)装置B的名称是:                    

(2)在洗涤操作中,第一次水洗的主要目的是:               ; 第二次水洗的主要目的是:                       

(3)在洗涤、分液操作中,应充分振荡,然后静置,待分层后       (填标号),

A.直接将乙酸异戊酯从分液漏斗上口倒出  

B.直接将乙酸异戊酯从分液漏斗下口放出

C.先将水层从分液漏斗的下口放出,再将乙酸异戊酯从下口放出

D.先将水层从分液漏斗的下口放出,再将乙酸异戊酯从上口放出

(4)本实验中加入过量乙酸的目的是:                             

(5)实验中加入少量无水硫酸镁的目的是:                                        

(6)在蒸馏操作中,仪器选择及安装都正确的是:                   (填标号)

(7)本实验的产率是:        

A.30℅             B.40℅               C.50℅              D.60℅

(8)在进行蒸馏操作时,若从130 ℃开始收集馏分,产率偏      (填高或者低)原因是             

阅读理解

Midas was a powerful king, both rich and greedy. Once he did a great favor for Bacchus, the god of wine. Bacchus offered Midas his choice of a reward. Midas answered at once. He asked that whatever he touched be turned into gold. Bacchus agreed, though he was sorry that Midas had not made a wiser choice.

Midas was eager to put his newly gained power to the test. He pulled a branch from a tree. The branch became gold in his hand. He picked up a stone; it turned to gold. He touched the grass, it, too, turned to gold.

Midas was overjoyed. Returning home, he ordered his servants to prepare a magnificent meal. But when he picked up some bread, it turned to gold. He lifted a glass of wine to his lips. But before he could taste it, it turned to gold.

Midas wished to free himself of his power. He hated the gift he had so recently hoped for. He raised his arms and begged and prayed for Bacchus to take away his deadly gift.

Bacchus showed pity. “Go,” he said. “to the River  Pactolus. There dip yourself in. Wash away your greed and its punishment. ”Midas did so. Hardly had he touched the waters, before the gold-making powers passed into them. The river sands changed into gold. And they remain golden to this day.

小题1:What is the moral of this story?

A.There is more to life than riches.

B.Gold is more important than food.

C.You can’t trust your friends.

D.You must make a wiser choice.小题2:When everything he touched turned to gold, Midas felt ______

A.happy and joyful

B.sad and disappointed

C.excited and angry

D.powerful and satisfied小题3:What was Midas’ wish after he could have nothing to eat?

A.To have a big meal.

B.To gain power to turn things to gold.

C.To have his power taken away.

D.To wash himself in the water.小题4:Today when we say that a person has the “Midas Touch”, we mean that ______

A.the person is very poor

B.gold is the most important thing to that person

C.everything that the person does makes money

D.the person has the power to do everything