问题 选择题

在0.1 mol/L的NH3·H2O溶液中,下列关系正确的是(   )

A.c(NH3·H2O)>c(OH-)>c(NH4+)>c(H+)

B.c(NH4+)>c(NH3·H2O)>c(OH-)>c(H+)

C.c(NH3·H2O)>c(NH4+)=c(OH-)>c(H+)

D.c(NH3·H2O)>c(NH4+)>c(H+)>c(OH-)

答案

答案:A

【错解分析】电解质溶液中离子浓度大小比较问题,是高考的“热点”之一。多年以来全国高考化学试卷年年涉及这种题型。这种题型考查的知识点多,灵活性、综合性较强,有较好的区分度,它能有效地测试出学生对强弱电解质、电离平衡、水的电离、pH、离子反应、盐类水解等基本概念的掌握及对这些知识的综合运用能力。

【正解】NH3·H2O是一元弱酸,属于弱电解质,在水溶液中少部分发生电离(NH3·H2ONH4++OH-),所以c(NH3·H2O)必大于c(NH4+)及c(OH-)。因为c(OH-)=c(NH4+)+C(H+),所以c(OH-)>c(NH4+)。综合起来,c(NH3·H2O)>c(OH-)>c(NH4+)c(H+),选择A选项。

完形填空
Our three-year-old daughter Becky wanted a dog. But we were too busy to buy one. One day, Becky ran in, shouting, “Mom! Come to see my dog!” Her face was red with   36 .
  I followed her to the bush and found a   37 ! He was hurt. Seeing me, he stood up   38 ! I could see his teeth! God! My mouth felt dry. “Don’t be afraid. That’s Mom. She  39 you, too.” Becky said. Then he became friendly. It was  40 !
  I   41  to find my husband and told him about the wolf. We should have  42  the wolf, but Becky loved him. Besides, he was gentle(温柔的) to Becky. So we called the vet finally.
  Becky named the wolf (狼) Ralph ,  43  she carried food to him every day. Later, Ralph got well. They played together in the daytime. At night, Ralph would return to the mountains. Sometimes he   44  but came back several days later.
  On Becky’s first day of school, we could see Ralph’s   45 . After the school bus left, Ralph lay by the side of the road and   46  . When Becky returned, he got happy again. This    47  throughout Becky’s school years.
  Twelve   48  passed.
  One day we heard that a she-wolf was killed. The other wolf was hurt and ran away. We were   49  about Ralph. That night, Ralph returned with a wound (伤). Fifteen-year-old Becky held his head and   50  him. We hope he could come through. However, he   51 .
  Becky cried. I noticed something strange in the bush — two little yellow eyes! Ralph’s  52 ! Before he died, Ralph   53  his child to us! He knew he would be  54  here, as he had been. Ralph, Ralph... I was   55 .
  “Don’t be afraid, little ... Ralphie. That’s Mom. She loves you, too.”
小题1:
A.encouragementB.entertainmentC.agreementD.excitement
小题2:
A.dogB.foxC.wolf D.tiger
小题3:
A.lovelyB.finallyC.suddenlyD.patiently
小题4:
A.hurtsB.lovesC.killsD.hates
小题5:
A.wonderfulB.unhappyC.unbelievableD.normal
小题6:
A.preparedB.rushed C.pretendedD.wanted
小题7:
A.lovedB.foundC.damagedD.killed
小题8:
A.andB.butC.soD.or
小题9:
A.disappearedB.turnedC.passedD.came
小题10:
A.sadnessB.dreamC.understandingD.anger
小题11:
A.sleptB.leftC.sangD.waited
小题12:
A.stoppedB.joinedC.livedD.continued
小题13:
A.daysB.weeksC.monthsD.years
小题14:
A.surprisedB.puzzledC.worriedD.careful
小题15:
A.comfortedB.beatC.washedD.amused
小题16:
A.succeededB.diedC.criedD.woke
小题17:
A.motherB.fatherC.wifeD.child
小题18:
A.postedB.broughtC.soldD.threw
小题19:
A.safeB.happyC.warmD.friendly
小题20:
A.confusedB.disappointedC.moved D.frightened
单项选择题