问题 问答题

A、B、C、D是初中化学课本中出现的各不相同的4种物质,它们都含有相同的一种元素,其中A是一种黑色粉末,它们之间的转化关系如图所示.请你分析,然后回答:

(1)用化学式表示:A:______;D:______;

(2)写出A→B的化学方程式:______,该反应属于______(填序号).

①置换反应  ②化合反应  ③分解反应   ④复分解反应.

答案

A是一种黑色粉末,则A可能是碳,碳能燃烧生成二氧化碳,则B可能是二氧化碳,二氧化碳能与氢氧化钙反应生成碳酸钙沉淀,则C可能是碳酸钙,碳酸钙能与水和二氧化碳转化生成碳酸氢钙,碳酸氢钙能分解生成二氧化碳,代入框图,推断合理,

(1)A是碳,D是碳酸氢钙,故填:C,Ca(HCO32

(2)碳能燃烧生成二氧化碳,该反应属于化合反应,故填:C+O2

 点燃 
.
 
CO2,②.

完形填空
Seven loyal(忠实的)readers came to the Teens Office two weeks ago. They had a wonderful day learning how to make a newspaper. But what  36  made them excited was that they had their say. 
“What most _37_ me was when I was saying something, I found all eyes were on me,” said Tang Shining, one of the students. Her friend, Li Chunbei _38_, and felt very glad that when she was talking, the editors(编辑) nodded and _39_ took notes.
Students are happy to see the editors listen to their _40_. You may often _41_about being neglected(忽视) by teachers and parents. _42__ before complaining, please make sure that you have already spoken about your _43_.
Traditionally in China, teachers at school and parents were_44_ the ones to tell teenagers what they should and shouldn’t do. The young are _45_ to doing what they are told, rather than thinking by themselves. But then their ideas would be locked in their brain and not be _46_.
A girl wrote to Teens about her family story. She _47__ to be very sad because her father seldom talked and played with her. After years of consideration, she _48_ decided to write her father a letter, telling him about her sadness. To her _49__, the father _50_, saying that he didn’t realize his mistake. From then on, he really _51_.
Sometimes, we need to let our _52__ be heard, so others can understand our thoughts and feelings.
Don’t be afraid of being _53_ for what you have done. You know it is your _54_ to speak your mind. Even if your suggestions are denied, at least you have tried your best. You will not be left with any _55_.
小题1:
A.directlyB.reallyC.completelyD.immediately
小题2:
A.disappointedB.frightenedC.impressedD.horrified (恐惧)
小题3:
A.refusedB.disagreedC.dislikedD.agreed
小题4:
A.evenB.yetC.alreadyD.still
小题5:
A.speechesB.opinionsC.songsD.articles
小题6:
A.talkB.complain C.writeD.speak
小题7:
A.AndB.SoC.ButD.Instead
小题8:
A.pleasureB.loveC.hatred(憎恨)D.worry
小题9:
A.seldomB.neverC.alwaysD.sometimes
小题10:
A.usedB.reducedC.devotedD.told
小题11:
A.rememberedB.usedC.touchedD.heard
小题12:
A.usedB.pretendedC.seemedD.had
小题13:
A.sadlyB.suddenlyC.angrilyD.finally
小题14:
A.sorrow(悲伤)B.disappointmentC.surpriseD.satisfaction
小题15:
A.apologizedB.smiledC.laughedD.sighed
小题16:
A.exchangedB.changedC.leftD.played
小题17:
A.voicesB.decisionsC.suggestionsD.secrets
小题18:
A.praisedB.blamedC.beatenD.fined
小题19:
A.dutyB.taskC.rightD.pleasure
小题20:
A.regret B.sadnessC.troubleD. difficulty
判断题