题干

设NA为阿伏加德罗常数的值,下列说法正确的是(    )

A:将1mol SO2通入水中,H2SO3、HSO3-、SO32-粒子数之和为NA

B:标准状况下,22.4L HF溶于水,溶液中HF与F数目之和为1NA

C:将1mol NH4NO3溶于稀氨水中使溶液呈中性,溶液中NH4+数目为NA

D:25℃时,pH=13的Ba(OH)2溶液中含有的氢氧根离子数为0.1NA

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答案(点此获取答案解析)

C

同类题2

根据材料内容,从下面的五个选项中选出能填入文中空缺处的最佳选项,使短文意思通顺,内容完整,并将其标号填写在下面题号后的横线上。

                                                                        (C)

      If you think you're too shy and want to be a little braver, try the following. You can make it.

             There's no need to hide it. When they get to know you're a shy kid, they'll understand you better. This also helps you feel easier in talks.

              When you smile, people think you're friendly and easy to talk with. Remember that other people have feelings, too, and ①most people will stay away from an angry-looking face.

      Take one small step at a time. If you find it hard to start talks, say something nice about people around you.         Doesn't it make you want to keep talking to that person?

      Turn your attention elsewhere.         ②Don't waste(浪费) time worrying about your looks or whether people like you or not Don’t lose heart Each time after you say “hi” or smile at someone for the first time, say “I did it!” to yourself.        

Keep trying and one day you'll never be shy when you talk to others.

A. Try to smile more.

B. Tell people you're shy.

C. Or it could be something bigger, like buying yourself an ice cream.

D. Think about how great you feel when someone says something nice to you.

E. Think more about ways to enjoy the party or the game.