问题 填空题

(创新预测题)(1)①在淀粉碘化钾溶液中,滴加少量次氯酸钠碱性溶液,立即会看到溶液变蓝色,这是因为________,离子方程式为__________________________。

②在碘和淀粉形成的蓝色溶液中,滴加亚硫酸钠碱性溶液,发现蓝色逐渐消失,这是因为______________________________。离子方程式是_______________________________。

③对比①和②实验所得的结果,将I2、ClO、SO42性由强到弱的顺序排列为_____________________________。

(2)今有铁片、铜片,设计实验证明以下事实,并写出反应的化学方程式。

①浓硫酸的氧化性比稀硫酸强。________________________________。

②氯化铁溶液中Fe3的氧化性比硫酸铜溶液中的Cu2强。__________________________。

③铁的还原性比铜强。

___________________________________________________________。

答案

(1)①NaClO将KI氧化生成了I2

ClO+2I+H2O=I2+Cl+2OH

②I2被Na2SO3还原生成了

SO32+2OH=SO42+H2O

③ClO>I2>SO42

(2)①Cu与浓硫酸反应而与稀硫酸不反应。

Cu+2H2SO4(浓) +SO2↑+2H2O

②Cu能与FeCl3溶液反应,

2FeCl3+Cu=2FeCl2+CuCl2

③Fe能与CuSO4溶液反应置换出Cu,

Fe+CuSO4=FeSO4+Cu(答案不唯一,合理即可)

(1)利用淀粉遇I2变蓝的特性验证NaClO的氧化性和Na2SO3的还原性,书写化学方程式时注意溶液环境为碱性。(2)列举常见反应事实即可。

填空题
完形填空
Have you ever tried to draw a straight line, only to find it turns out all wrong? Or, have you ever wanted to show ___36___ at a party and found the song you’d practiced so many times suddenly__37_ more difficult? I’ve had both these__38___. As a senior student, I have to ___39__ many exams. Each time, I think, “ I__40___ fail this time,’’ but I get a low mark. Don’t be surprised---it’s not __41___ I don’t try, do enough preparation, __42__ take it seriously. On the contrary, it is because I give it too _43__ attention. The thought “ I must pass” makes me taste the terrible flavor of failure.
I often___44___ to my friends, “ Don’t be too hard ___45____ yourself.” However, when I __46___ my own goals, I do not listen to my own advice. So why not ___47__ this crazy thought of achieving the best? Just face the problem__48____before you with a calm mind, work and you will succeed.
In my opinion, __49___ a calm state of mind is a skill for life. People__50__ want to succeed realizing this is of __51______ importance. So __52___ time you’re trying to draw a straight line or ___53___ a performance, tell yourself, “ If I can just do it _54___ than last time, it’s a success.” Keep a calm state of mind, and you will be happy __55____you succeed or fail.
小题1:
A.aroundB.offC.outD.in
小题2:
A.becameB.becomeC.becomingD.becomes
小题3:
A.experiencesB.experienceC.times D.difficulties
小题4:
A.enterB.makeC.takeD.join
小题5:
A.won’tB. can C.needD.needn’t
小题6:
A.because ofB./C.thereforeD.because
小题7:
A.andB.orC.butD.nor
小题8:
A.manyB.fewC.littleD.much
小题9:
A.sayB.adviseC.tellD.encourage
小题10:
A.offB.onC.toD.for
小题11:
A.giveB.holdC.buildD.set
小题12: A. throw away      B. get away         C. take up         D push off
小题13:
A.lieB.liesC.lyingD.laying
小题14:
A.keepingB.stayingC.remainingD.making
小题15:
A.whomB.whichC.whoD./
小题16: A no                B. little         C. very           D. great
小题17:
A.lastB.the lastC.nextD.the next
小题18:A. put on             B play on                C. give on         D show on
小题19:
A.bestB.betterC.goodD.well
小题20:
A.ifB.eitherC.neitherD.whether