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问题 选择题

在一定条件下，对于密闭容器中进行的可逆反应：，下列说法中，表明这一反应已达到化学平衡状态的是

A．的浓度相等　　　　

B．反应停止，正、逆反应速率都等于零

C．在密闭容器中共存　　

D．的浓度不再变化

答案

答案：D

填空题

短文填词。

    One day Mr White stayed very l   1   in a restraurant. When he got home at ten o'clock,    Mrs White

was s  2   at the dinner table waiting for him. Instead of blaming him, she readily a     3  him if he wanted

to eat something. He said he didn't.

    At half past 3,the alarm clock made a   4   noise. He got up in a hurry and t   5   on  the light. After k  6   what time it was , he s  7   at his wife and asked her to make an explanation(解释). "Hmm,"she

answered,"If it t    8    you five hours to get home from work,  then I think it takes you just as l   9    to

go to work. I don't h  10  you'll be late."

1.                2.                3.              

4.                5.                6.              

7.                8.                9.              

10.              
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问答题

用一根不知有无磁性的铁棒的A端靠近一根悬挂的条形磁铁的N极，磁铁靠近铁棒，如图中甲所示，则可判断铁棒______带有磁性（“一定”、“不一定”）；若改将铁棒的B端靠近悬挂的条形磁铁的N极，磁铁远离铁棒，如图中乙所示，则可判断铁棒一定带有磁性，且A端为______极（填“N”、“S”）．
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