用中和滴定法测定某烧碱样品的纯度,试根据实验回答下列问题: (1)准确称量8.2

题型:填空题

问题:

用中和滴定法测定某烧碱样品的纯度,试根据实验回答下列问题:

(1)准确称量8.2g含有少量中性易溶杂质的样品,配成500mL待测溶液.称量时,样品可放在______(填编号字母)称量.

A.小烧杯中

B.洁净纸片上

C.托盘上

(2)滴定时,用0.2000mol•L-的盐酸来滴定待测液,不可选用______(填编号字母)作指示剂.

A.甲基橙     B.石蕊     C.酚酞

(3)滴定过程中,眼睛应注视______,在铁架台上垫一张白纸,其目的是______

(4)根据下表数据,计算被测烧碱溶液的物质的量浓度是______mol•L-,烧碱样品的纯度是______

滴定次数待测溶液体积(mL)标准酸体积
滴定前刻度(mL)滴定后刻度(mL)
第一次10.000.4020.50
第二次10.004.1024.00
(5)下列实验操作会对滴定结果产生什么后果?(填“偏高”、“偏低”或“无影响”)

①若将锥形瓶用待测液润洗,然后加入10.00mL待测液,则滴定结果______

②若锥形瓶未干燥就加入10.00mL待测液,则滴定结果______.

考点:酸碱中和滴定
题型:填空题

以下生物碱属于莨菪烷类的有

A.吗啡

B.莨菪碱

C.阿托品

D.樟柳碱

E.东莨菪碱

题型:填空题

下列括号内的英文简称与其中文名称对应的是()

A.协议(ProtoCol)

B.国际标准化组织(OSI)

C.局域网(LAN)

D.国际电气电子工程师学会(IEEE)

题型:填空题
Mr. Jones had always wanted to make a trip into the middle of Africa to shoot wild animals. 36  first he had no enough money, and then he was married. His wife had not wanted him to37 her. At last his wife  38  to the trip if he allowed her to go, too.
“But it will be very uncomfortable,” Mr. Jones  39 her, “ It will be very hot and we shall live in a tent, and it  40  be dangerous. ”“I don’t care,” said his wife, “I want to go with you.” So they bought a big tent, camp beds, a refrigerator which did not need  41  and many other things which would make the trip 42, and went off to the middle of Africa.
The first morning,  43  Mr. Jones took his gun and left the tent, he  44  his wife a bell and explained to her , “If you fall in  45  and you need me ,  46  this bell and I’ll come at once.”
After a few minutes, he heard the bell and returned 47   to the tent. “What’s the matter?” he asked.“  48  ” said his wife, “I was only  49  the bell.” Mr. Jones went off, but after a quarter of an hour, the bell rang again .
Mr. Jones hurried back to the tent, but his wife said, “I’m  50 . I was cleaning our tent, and I knocked the bell over by mistake.” Mr. Jones returned to his  51 , but soon he heard the  52  once more. This time, when he got back to his   53  , the tent was burning and Mrs. Jones was lying on the ground, with  54  running from a big cut on her shoulder. “That’s better!” said Mrs. Jones. “This time the bell had been used 55 !”
小题1:
A.AndB.ButC.ForD.Although
小题2:
A.leaveB.missC.marryD.care
小题3:
A.allowedB.promisedC.satisfiedD.agreed
小题4:
A.toldB.advisedC.persuadedD.warned
小题5:
A.mayB.mustC.can’tD.shall
小题6:
A.moneyB.electricityC.forceD.power
小题7:
A.differentB.comfortableC.perfectD.interesting
小题8:
A.whileB.untilC.beforeD.after
小题9:
A.gaveB.sentC.lentD.bought
小题10:
A.hurryB.surpriseC.safetyD.danger
小题11:
A.hitB.knockC.beatD.ring
小题12:
A.againB.backC.quicklyD.finally
小题13:
A.SomethingB.NothingC.NoD.None
小题14:
A.ringingB.tryingC.usingD.testing
小题15:
A.happyB.sorryC.tiredD.all right
小题16:
A.wifeB.tentC.tripD.hunting
小题17:
A.cryB.shotC.bellD.shout
小题18:
A.gardenB.houseC.campD.office
小题19:
A.waterB.tearsC.bloodD.sweat
小题20:
A.correctlyB.wronglyC.frequentlyD.carefully
题型:填空题

下列各组腧穴中,相距不是1寸的是()。

A.中极、关元

B.下脘、中脘

C.中脘、上脘

D.内关、间使

E.外关、支沟

题型:填空题

道岔扣件系统及其零部件应满足以下说法正确的是()

A.道岔扣件系统安装与调整应符合铺设图要求,各零部件应保持齐全,作用良好

B.应使用铁路专用防腐油脂定期对螺栓涂油,螺栓保持润滑状态

C.不得对转辙器滑床台涂油,辙叉滑床台可涂固体润滑剂。各部位螺栓涂油时不得污染橡胶垫板、弹性铁垫板和弹性基板

D.轨距块、挡板、缓冲调距块、偏心锥等严重磨损应及时更换

更多题库