在A、B、C、D四种元素原子的核电荷数均小于18，且依次增大．A、C_爱下问搜题

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问题填空题

在A、B、C、D四种元素原子的核电荷数均小于18，且依次增大． A、C可按原子个数比为1：1或2：1形成X、Y两种常见化合物，常温下为液态，B、C可按原子个数比为1：1或1：2形成M、N两种常见化合物，常温下为气态，N能使澄清石灰水变浑浊，D、C 可按原子个数比为1：2或1：3形成Q、R两种化合物，Y能分别与Q、R发生化合反应得到两种产物的水溶液常温时pH都小于7．

（1）写出有关物质的化学式，X为______，Y为______．

（2）X也能与Q发生化合反应，其化学方程式为______．

（3）当两微粒的原子个数相等、核外电子数之和也相等时，可互称为等电子体．如：SO₂与O₃、CN^-与N₂互为等电子体，写出与N₂O互为等电子体的一种微粒的化学式______．

答案

A、C可按原子个数比为1：1或2：1形成X、Y两种常见化合物，常温下为液态，说明A是氢元素，B是氧元素，那么X就是过氧化氢，Y就是水；N能使澄清石灰水变浑浊，说明N是二氧化碳，所以B就是碳元素，M就是一氧化碳；D、C 可按原子个数比为1：2或1：3形成Q、R两种化合物，Y能分别与Q、R发生化合反应得到两种产物的水溶液常温时pH都小于7，说明D是硫元素，Q就是二氧化硫，R就是三氧化硫．

（1）X就是过氧化氢，化学式为：H₂O₂；Y是水，化学式为：H₂O；

（2）X也能与Q发生化合反应，其化学方程式为H₂O₂+SO₂=H₂SO₄；

（3）N₂O中电子数为22，N₂O与CO₂均为22个电子，所以互为等电子体．

故答案为：（1）H₂O₂；H₂O；（2）H₂O₂+SO₂=H₂SO₄；（3）CO₂．

单项选择题共用题干题

如因深龋需进行间接盖髓治疗。

间接盖髓的目的（）。

A.安抚镇痛

B.促进修复性牙本质形成

C.消毒窝洞

D.隔绝外界刺激

E.以上都不是

完形填空

Is it difficult for you to get up in the morning? Do you sometimes oversleep？ Are you often late for work or school? Yes? Then Hiroyuki Sugiyama of Japan has a(an)    16    bed for you. Hiroyuki’s bed will get you up in the morning! Here is how it      17   .
The bed    18  an alarm clock. First, the alarm clock rings. You have a few minutes to wake up. Next, a tape recorder in the bed plays   19  music or other pleasant sounds.The tape recorder in Hiroyuki’s bed plays a recording of his girlfriend. She whispers in a sweet   20      , "Wake up, darling, please." A few minutes later, a second recording    21   . The sound recording can be loud music or    22    sounds. Hiroyuki hears a recording of his boss shouts, "Wake up immediately,   23  you’ll be late!"
If you don’t get up    24   the second recording, you will be sorry! A mechanical
"foot" is in the bed. The mechanical foot kicks you in the head. Then the bed waits a few   25   minutes. What! You’re still in bed! Slowly the    26   of the bed rises higher and higher. The foot of the bed goes lower and lower.         27     the bed is vertical(垂直的). You slide off the bed and onto the floor. You are out of bed and    28 .
Hiroyuki made his bed because he wanted to     29    a contest. He works for Honda Motor Company. Once every two years Honda has a contest for its 200,000 employees---"All-Honda Idea Contest", The employees think of new ideas. If their ideas win, the employees win   30   . Hiroyuki Sugiyama won a lot of money for his bed.

D．comfortable

A．is separated from	B．is made up of
C．is attached to	D．is made into

B．interesting