题干

NA表示阿伏加德罗常数,下列叙述正确的是(   )

A:在0.1mol/L碳酸钠溶液中阴离子总数大于0.1NA

B:在铜与硫的反应中,1mol铜失去电子数2NA

C:31g白磷分子中,含有的共价单键数目是NA

D:向含0.1mol NH4Al(SO4)2的溶液中滴加NaOH溶液至沉淀恰好完全溶解,消耗的OH- 数为0.5NA

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答案(点此获取答案解析)

D

同类题2

阅读下面信息,用恰当的词完成下面的短文,每空一词。

    Square dancing has been popular for quite a few years.  Its lovers believe it is good for elderly people's health But in recent years, it has many haters as well. They think too loud music or dancing too late into night influences people's life. Should square dancing be supported or limited? Here are opinions from two groups of people.

For

    Square dancing is a helpful way for elderly people to stay fit.

    Square dancing has become an important socializing opportunity(社交机会) for those parents whose grown children have left to start their own families.

    If governments provide large places where people can dance a bit far from living blocks, most of the complaints will go away.

Against

    Square dancing in public may not be acceptable to all elderly people. Some of them hate the noise caused by such kind of dancing.

    Square dancing is something that elderly people themselves invented. They just want to be left by themselves to do what they like.

    There are some other healthier ways to exercise for people from different age groups and with different health .situations. Square dancing is not a good idea for everyone.

    Square dancing has been a hot topic in daily life. People have been discussing ____ it should be supported or limited. Lovers believe it can help elderly people stay healthy. Those parents who live ____ can communicate with others while dancing. If people are ____ with large places by governments and they can dance a bit far away from living blocks, few neighbours will complain. Haters say the noise caused by square dancing is the main ____ why they are against it. They think square dancers just do what they like to do without ____ others' feelings. And square dancing.is not the only good way for all people to exercise.