用NA表示阿伏伽德罗常数的值.下列叙述正确的组合是( ) ①2.3gNa和足量的

题型:选择题

问题:

用NA表示阿伏伽德罗常数的值.下列叙述正确的组合是(  )

①2.3g Na和足量的O2完全反应,在常温和燃烧时,转移电子数均为0.1NA

②含0.2mol H2SO4的浓硫酸与足量铜反应,生成SO2的分子数为0.1NA

③标准状况下,2.24L Cl2通入足量H2O或NaOH溶液中转移的电子数均为0.1NA

④25℃时,pH=13的1.0LBa(OH)2溶液中含有的OH-数目为0.2NA

⑤100mL 1mol•L-1 AlCl3溶液中含阳离子数大于0.1NA 

⑥含有NA个NO2、N2O4分子的混合气体,降低温度,混合气体的分子总数小于NA

A.①②⑥

B.②④⑥

C.③⑤⑥

D.①⑤⑥

考点:阿伏加德罗常数
题型:选择题
In the clinic, I asked if Michael could be retested, so the specialist tested him again. To my __36__, it was the same score.
Later that evening, I _37_ told Frank what I had learned that day. After talking it over, we agree that we knew our _38_ much better than an IQ test. We _39_ that Michael’s score must have been a __40___ and we should treat him ___41___ as usual.
We moved to Indiana in 1962, and Michael studied at Concordia High School in the same year. He got _42 _ grades in the school, especially _43_ biology and chemistry, which was a great comfort.
Michael _44_ Indiana University in 1965 as a pre-medical student, soon afterwards, his teachers permitted him to take more courses than _45_. In 1968, he was accepted by the School of Medicine, Yale University.
On graduation day in 1972, Frank and I _46_ the ceremony  at Yale. After the ceremony, we told Michael about the _47_ IQ score he got when he was six. Since that day, Michael sometimes would look at us and say _48_, “My dear mom and dad never told me that I couldn’t be a doctor, not until after I graduated from medical school!” It is his special way of thanking us for the _49_ we had in him.
Interestingly, Michael then _50_ another IQ test. We went to the same clinic where he had _51_ the test eighteen years before. This time Michael scored 126, an increase of 36 points. A result like that was supposed to be _52_.
Children often do as _53_ as what adults, particularly parents and teachers, _54_ of them. That is, tell a child he is “ _55_”, and he may play the role of a foolish child.
小题1:
A.joyB.surpriseC.dislikeD.disappointment
小题2:
A.tearfullyB.fearfullyC.cheerfullyD.hopefully
小题3:
A.studentB.sonC.friendD.doctor
小题4:
A.arguedB.realizedC.decidedD.understood
小题5:A. joke           B. mistake      C. warning          D wonder.
小题6:
A.speciallyB.strictlyC.naturallyD.carefully
小题7:
A.poorB.goodC.averageD.standard
小题8:
A.in B.aboutC.ofD.for
小题9:
A.visitedB.choseC.passedD.entered
小题10:
A.allowedB.describedC.requiredD.offered
小题11:
A.missedB.heldC.delayedD.attended
小题12:
A.highB.sameC.lowD.different
小题13:
A.curiouslyB.eagerlyC.calmlyD.jokingly
小题14:
A.faithB.interestC.prideD.delight
小题15:
A.looked forB.asked forC.waited forD.prepared for
小题16:
A.receivedB.acceptedC.organizedD.discussed
小题17:
A.imperfectB.impossibleC.uncertainD.unsatisfactory
小题18:
A.honestlyB.muchC.well D.bravely
小题19:
A.hear B.learnC.expectD.speak
小题20:
A.wiseB.rudeC.shyD.stupid
题型:选择题

某试验室在进行混凝土抗压试验时,发现试验条件的改变会影响试验值,请就以下各类情况作出判断(判断题):

进行混凝土抗压试验时,当试件高宽比加大,试验值将偏大。

题型:选择题

室间隔缺损,房间隔缺损,动脉导管未闭及法洛四联症,上述的先天性心脏病患儿平时最常见的并发症是()。

A.肺炎

B.脑栓塞

C.心律失常

D.喉返神经麻痹

E.感染性心内膜炎

题型:选择题

分割屏、后屏、高温过热器检查方法和检查内容有哪些?

题型:选择题

其中f(u,v)是连续函数,则dz=______.

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