问题 选择题

能正确表示下列反应的离子方程式是 (  )

A.向KHSO4溶液中加入Ba(OH)2溶液至恰好沉淀完全

Ba2++OH+H++SO42=BaSO4↓+H2O

B.铁跟稀硫酸反应:2Fe + 6H+ ═ 2Fe3+ + 3H2

C.碳酸钙与醋酸反应:CaCO3+2H+ ═ Ca2+ + CO2↑ + H2O

D.硫酸铜溶液跟氢氧化钡溶液反应:Ba2+SO42=BaSO4

答案

答案:A

题目分析:B不正确,铁和稀硫酸反应生成硫酸亚铁和氢气;C不正确,醋酸是弱酸,应该用化学式表示;D不正确,反应中还有氢氧化铜蓝色沉淀生成,因此正确的答案选A。

点评:该题是高考中的高频题,属于中等难度的试题,试题侧重考查学生的能力。该题需要明确判断离子方程式正确与否的方法一般,即(1)检查反应能否发生。(2)检查反应物、生成物是否正确。(3)检查各物质拆分是否正确。(4)检查是否符合守恒关系(如:质量守恒和电荷守恒等)。(5)检查是否符合原化学方程式,然后灵活运用即可。该题有助于培养学生分析问题、解决问题的能力。

完形填空
Letting go of success
I want to make the most of every day. And, like most people, I've____ that the best way to do it is to let go of past failures. But that's not all. One can never fully ____ today while thinking too much about past successes, either. People never ____ while resting comfortably on their laurels (荣誉). The ___ is that sometimes our successes hold us back more than our failures!
I once ____ a story about the Oscar owner, actor Clark Gable. A friend ____ Gable one afternoon at the actor's home. She brought along her ____ son, who was playing happily with toy cars on the floor. He____ he was racing those cars around a great track, which in ____ was an imaginary circle around a golden statue (雕像). The small statue the boy played with was actually the Oscar Clark Gable ____ for his performance in the 1934 movie It Happened One Night.
When his mother told him the time had come to ____, the little boy asked the actor, “Can I have this?” ____ to the Oscar.
“Sure, ” he smiled. “It's yours.”
The horrified mother ____. “Put that back immediately!”
Giving the child the golden statue, Clark Gable said, “Having the Oscar around doesn't mean anything to me;   ____it does.” The actor seemed to know that past success could be a ____ hammock (吊床) upon which he may be tempted to____, rather than a springboard setting him to begin a new start.
You may have learned to let go of past ____ and mistakes in order to free the present. But will you forget past successes and achievements in order to free the ____? Will your past be a springboard or a restful hammock?
“I like the ____ of the future better than the history of the past,” said Thomas Jefferson. I ____. After all, the future, not the past, is where the rest of your life will be lived.
小题1:A discovered   B. inferred     C. hoped    D. worried
小题2:
A.spendB.liveC.understandD.enjoy
小题3:
A.struggleB.workC.succeedD.learn
小题4:
A.storyB.factC.ideaD.news
小题5:
A.wroteB.toldC.knewD.heard
小题6:
A.sawB.recognizedC.metD.visited
小题7:
A.carefulB.smallC.lonelyD.clever
小题8:
A.pretendedB.believedC.insistedD.suggested
小题9:
A.realityB.caseC.turnD.need
小题10:
A.caredB.askedC.wonD.looked
小题11:
A.actB.leaveC.playD.wait
小题12:
A.runningB.gettingC.pointingD.shouting
小题13:
A.objectedB.noticedC.sufferedD.breathed
小题14:
A.sellingB.keepingC.earningD.sharing
小题15:
A.specialB.comfortableC.expensiveD.necessary
小题16:
A.restB.cheatC.stopD.sit
小题17:
A.difficultiesB.eventsC.failuresD.achievements
小题18:
A.timeB.futureC.bodyD.brain
小题19:
A.ideaB.meaningC.dreamsD.thoughts
小题20:
A.obeyB.permitC.wishD.agree
单项选择题