今年9月29日，“天宫一号”成功发射，“天宫一号”在升天前加注

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问题选择题

今年9月29日，“天宫一号”成功发射，“天宫一号”在升天前加注的火箭燃料主要是偏二甲肼（C₂H₈N₂）和四氧化二氮（N₂O₄），下列有关偏二甲肼的说法不正确的是（　　）

A．偏二甲肼是由碳、氢、氮三种元素组成的

B．偏二甲肼的相对分子质量是60

C．偏二甲肼中碳、氢元素的质量比为3：1

D．偏二甲肼由2个碳原子、8个氢原子和2个氮原子构成

答案

A、偏二甲肼是由碳、氢、氮三种元素组成的，故选项说法正确．

B、偏二甲肼的相对分子质量是12×2+1×8+14×2=60，故选项说法正确．

C、偏二甲肼中碳、氢元素的质量比为（12×2）：（1×8）=3：1，故选项说法正确．

D、1个偏二甲肼分子是由2个碳原子、8个氢原子和2个氮原子构成的，故选项说法错误．

故选D．

选择题

下列曲线图与对应选项不正确的是( )

A．向1L浓度均为0.1mol·L^–1的Ba(OH)₂、NaAlO₂混合液中逐滴加入0.1 mol·L^–1稀H₂SO₄溶液

B．向1L 0.1 mol·L^–1 AlCl₃和0.3mol/L NH₄Cl的混合液中逐滴滴入0.1 mol·L^–1NaOH溶液

C．向烧碱溶液中逐滴加入明矾溶液

D．向Ba(OH)₂溶液中逐渐通入二氧化碳气体

查看答案

阅读理解

He was 11 years old and often went fishing. On the day before bass (鲈鱼) season opened, he and his father were fishing early in the evening.

When his pole doubled over, he knew something huge was on the other end. His father watched with admiration as the boy skillfully worked the fish. Finally, he lifted the tired fish from the water. It was the largest one he had ever seen, but it was a bass.

Lighting a match, the father looked at his watch. It was 10 pm — two hours before the season opened. He looked at the fish, then at the boy, saying, “You’ll have to put it back, Son.”

Looking around, he saw no other fisherman or boats. Even so, the boy could tell from his father’s voice that the decision couldn’t be changed. He threw the huge bass into the water. The boy thought that he would never again see such a big fish.

That was 34 years ago. Today the boy is a successful architect (建筑师) in New York. He often takes his son to fish at the same place.

And he was right. He has never again caught such a large fish as the one he got that night long ago. But he does see that same fish… again and again… every time he has an ethical (道德的) decision to make. As his father had taught him, ethics are simple matters of right and wrong. It is only the practice of ethics that is difficult.