现有H、O、H+、O2-、H2、O2、OH-、H2O八种粒子，试用这些粒子的符号_爱下问搜题

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问题填空题

现有H、O、H⁺、O^2-、H₂、O₂、OH^-、H₂O八种粒子，试用这些粒子的符号填空．

（1）能保持水的化学性质的粒子是______；

（2）氢气和氧气化合生成水的过程中的最小粒子是______；

（3）水变成水蒸气是______没有变化；

（4）电解水得到的产物是______；

（5）没有电子的粒子是______；

（6）质子数少于核外电子数的粒子是______．

答案

（1）分子是保持物质化学性质的最小粒子，水是由水分子构成的，所以保持水的化学性质的粒子是水分子（H₂O）；

（2）氢气和氧气化合时先分成氢（H）、氧（O）原子，原子是化学变化中的最小粒子；

（3）水变成水蒸气是物理变化，水分子（H₂O）本身没有变化；

（4）电解水得到的是氢气（H₂）和氧气（O₂），它们都是由分子构成的；

（5）氢原子核外只有一个电子，失去一个电子后氢离子（H⁺）没有电子；

（6）因为质子带正电荷，电子带负电荷，质子数少于核外电子数的粒子是阴离子（OH^-、O^2-）．

答案：（1）H₂O，（2）H、O，（3）H₂O，（4）H₂、O₂，（5）H⁺，（6）OH^-、O^2-．

单项选择题

当物体的密度小于介质的密度时，物体将在介质中（）。

A、悬浮

B、沉降

C、浮起

D、横移

完形填空

My daughter performed（表演） on behalf（代表） of her class in the annual（每年的） school concert today. She played so       that I could not help cheering her. The very        reminded me of her experiences of piano practicing.
When she was five, we gave her a piano as a birthday present. With great       , she began learning it. However, when she was no longer       , she became sick of （厌烦）it.       , it is a tough job to learn the piano, not to mention the daily routine（常规）of       .
When her first teacher left, my friend        me to an American teacher whose way of teaching was completely American. After practicing, she would give my daughter some        comments（评论）, and then point out what should be       . Every time she came,        beginning the lesson right away, she would first play some       . She said, “To learn the piano, you should learn not only the        of playing, but more importantly, to        the music and love it.”
After some time, my daughter became fond of her lessons. Sometimes she        would like to      a little bit when her skill had reached a certain level.
Surprisingly, my daughter said to me one day, “Mom, I was        that you didn’t give up my piano lessons. Learning it is like climbing a mountain. You’ll feel        when you are on the way. When you look        from where you are, you will realize that you have been making       . But if you       , you’ll never take one more step.” That was the very thing I wanted to teach her.

B．arrangement

A．unwillingness

D．First of all

C．interesting