题干

可逆反应:2NO2⇌2NO+O2在体积固定的密闭容器中,达到平衡状态的标志是(   )

①单位时间内生成n mol O2的同时生成2n mol NO2

②单位时间内生成n mol O2的同时生成2n mol NO

③用NO2、NO、O2的物质的量浓度变化表示的反应速率的比为2:2:1的状态

④混合气体的颜色不再改变的状态

⑤混合气体的密度不再改变的状态

⑥混合气体的压强不再改变的状态

⑦混合气体的平均相对分子质量不再改变的状态.

A:①③④⑤

B:②③⑤⑦

C:①④⑥⑦

D:全部

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答案(点此获取答案解析)

C

同类题1

阅读下面短文, 从短文后各题所给的四个选项(A、B、C、D)中, 选出可以填入空白处的最佳选项。

    Mickey was a nice, cheerful, optimistic boy. No one could remember ever having seen him 1; it seemed he didn't 2whatever people said to him. Even his teachers admired his good 3. It was so unusual that a story was going around that Mickey's 4 must be due to some special secret. They asked Mickey so much that he 5 his favorite teacher, Mr. Anthony, to tea one afternoon. When they had finished, Mickey 6 Mr. Anthony around the house. When Mickey opened his bedroom door, the teacher 7. The huge wall was a unique collage (拼贴画) of thousands of colors and shapes! It was the loveliest decoration Mr. Anthony had ever 8.

    “Some people at school think that I 9 think badly of anyone,” Mickey started to explain, “and that 10 at all bothers me, but that's not true at all. I'm just like anyone else. I used to get angrier than all the other kids. 11 years ago, with the help of my parents, I started a small collage. With every little piece I stuck on I added some bad thought or act.”

    It was 12. The teacher looked closely at the wall. In each one of the small 13 he could read “fool”, “silly”, “idiot”, “pain” , and a thousand other 14 things.

     “This is how I started 15 all my bad times into an opportunity to 16 to my collage. Now I like the collage so much that, each time someone makes me angry, I couldn't be17. They've given me a new piece for my work of 18.”

    That day, the teacher was impressed by Mickey's 19 to have an optimistic character. Without telling anyone, Mr. Anthony 20 his own collage and he would often recommend it to his students.