问题 选择题

六苯乙烷为白色固体,其结构表示如图:

下列有关说法中正确的是(  )

A.它是一种苯的同系物,易溶于有机溶剂

B.它的分子式为C38H30,只含有非极性键

C.它的一氯代物只有三种    

D.在同一平面上的原子最多有14个

答案

答案:C

题目分析:A.它含有苯环,但是不是苯的同系物,易溶于有机溶剂,错误;B.它的分子式为C38H30,含有C-C非极性键和C-H极性键,错误;C.它的一氯代物只能在苯环上,在与苯环连接的C原子的邻位、间位、对位三种不同的位置,正确;D.由于苯是平面分子,甲烷是正四面体分子,所以若一个平面通过正四面体的几何中心,最多可以通过两个顶点,因此在同一平面上的原子最多有11×2+1=23个.错误。

选择题
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How to Be a Winner

Sir Steven Redgrave

Winner of 5 Olympic Gold Medals

“In 1997 I was found to have developed diabetes(糖尿病). Believing my career was over, I felt extremely low. Then one of the specialists said there was no reason why I should stop training and competing. That was it — the encouragement I needed. I could still be a winner if I believed in myself. I am not saying that it isn’t difficult sometimes. But I wanted to prove to myself that I wasn't finished yet. Nothing is to stand in my way.”

Karen Pickering

Swimming World Champion

“I swim 4 hours a day, 6 days a week. I manage that sort of workload by putting it on top of my diary. This is the key to success — you can’t follow a career in any field without being well-organized. List what you believe you can achieve. Trust yourself, write down your goals for the day, however small they are, and you’ll be a step closer to achieving them.”

Kirsten Best

Poet & Writer

“When things are getting hard, a voice inside my head tells me that I can’t achieve something. Then, there are other distractions, such as family or hobbies. The key is to concentrate. When I feel tense, it helps a lot to repeat words such as ‘calm’, ‘peace’ or ‘focus’, either out loud or silently in my mind. It makes me feel more in control and increases my confidence. This is a habit that can become second nature quite easily and is a powerful psychological tool.”

小题1:What does Sir Steven Redgrave mainly talk about?

A.Difficulties influenced his career.

B.Specialists offered him medical advice.

C.Training helped him defeat his disease.

D.He overcame the shadow of illness to win.小题2:What does Karen Pickering put on top of her diary?

A.Her sports career.

B.Her achievements.

C.Her daily happenings.

D.Her training schedule.小题3:What does the underlined word “distractions” probably refer to?

A.Ways that help one to focus.

B.Words that help one to feel less tense.

C.Activities that turn one's attention away.

D.Habits that make it hard for one to relax.小题4:According to the passage, what do the three people have in common?

A.Self-confidence.

B.Hard work.

C.Devotion.

D.Courage.