用密度为1.84g/cm3,质量分数为98%的浓硫酸配制100mL 1.00mo

题型:实验题

问题:

用密度为1.84g/cm3,质量分数为98%的浓硫酸配制100mL 1.00mol/L 的稀硫酸。

(1)在容量瓶的使用方法中,下列操作不正确的是____________ 

A.使用容量瓶前检验是否漏水

B.容量瓶用水洗净后,再用待配溶液洗涤

C.配制溶液时,如果试样是固体,把称好的固体用纸条小心倒入容量瓶中,缓慢加水至接近刻度线1~2cm处,用胶头滴管加蒸馏水至刻度线。

D.配制溶液时,若试样是液体,用量筒取样后用玻璃棒引流倒入容量瓶中,缓慢加水至刻度线1~2cm处, 用胶头滴管加蒸馏水至刻度线。E.盖好瓶塞,用食指顶住瓶塞,另一只手托住瓶底,把容量瓶反复倒转多次,摇匀。

(2)经计算,上述浓硫酸的浓度为_______ mol/L。配制100mL1.00mol/L的稀硫酸,应用量筒量取浓硫酸的体积为_______mL(保留一位小数),量取时应选用_______ (填序号①10mL、②50mL 、③100mL)规格的量筒。

(3)请将下列步骤补充完整:

a.量取所需浓硫酸在烧杯中加适量蒸馏水溶解,待溶液冷却到室温后将其沿玻璃棒移入    mL的容量瓶中,并将洗涤液移入容量瓶中。

b.向容量瓶内加水,直到液面接近刻度线       cm时,改用         小心地加水至溶液凹液面与刻度线相切。

c.将容量瓶盖好瓶盖,摇匀。

(4)配制过程中如果出现下列情况,会使溶液物质的量浓度如何变化?(填“偏高”、“偏低”或“不变”)

转移时未洗涤烧杯,则结果         

所用容量瓶未干燥,则结果           ;     

定容时俯视,则结果              

考点:物质的量
题型:实验题

金黄色葡萄球菌感染形成的脓液为()

A.翠绿色稍粘稠有酸臭味

B.黄色粘稠

C.淡黄色稀薄

D.灰白色或灰褐色、腐臭味

E.灰白色米汤样,含干酪样坏死物

题型:实验题

任务型阅读。请仔细阅读第1-5题中的个人情况说明,然后从A到F的六个选项中选出合适的选项与之匹配。其中有一项多余。(共5小题,计10分)

小题1:Jack and Peter, both teachers, are going to take their summer holidays at the beautiful seaside. They like good wine and shopping.

小题2: Chen Hui and Li Hong, university students, want to travel with very little money, and would like to get to know the country by working with the local (当地的) people for two weeks.

小题3:Mr Zhang, a young manager, needs a holiday to relax. He would like to go somewhere warm and sunny, where he can swim in the sea, and he enjoys sports and dancing.

小题4:Mr Lee and his wife, who have recently retired,want to see places of cultural and historic interest, but Mrs Lee hates flying.

小题5: Ling Xia, a nurse in a hospital in Guangzhou, hopes to spend her 21st birthday in the north of China. And she hopes to skate on real ice.

A.Seven Days on Jinsha Island

Seven-day holidays on Jinsha Island, lovely beaches with golden sand and deep blue sea. Sailing and some other water sports as well as dancing to local music.

B.East China in Comfort

Comfortable coach tours around five cities in East China. Six days out of normal holiday season, learning about local culture

C.A Four-day Holiday in Guilin

Relax yourselves during a four-day holiday in Guilin. Go by air, Stay in Lijiang Hotel. Taste delicious Guilin rice noodles. A tour on Lijiang River by boat.

D.Holiday Homes in SanyaHoliday flats in Sanya in summer by the sea, yet near shops and restaurants.

E.One Week on Sun Island, Harbin

One-week holiday in Full Moon Hotel. Beautiful flats with signs of Sun Lake. Skating, skiing and other winter sports.

F. Farm Holidays in Guizhou

Working holidays on a farm in Guizhou for 10—90 days, if you want to work with the farmers. Rooms and food are all provided for free—you only pay for the traffic cost.

题型:实验题

RNC单板使用的嵌入式处理器不包括()

A.通用处理器(X86,X86/2,8260,85xx等)

B.DSP数字信号处理器

C.NP网络处理器

D.FPGA可编程门阵列

题型:实验题

(EMB145)关于马赫数的显示,哪项是正确的?()

A.马赫数的显示范围是0.05到0.85马赫

B.当空速大于0.45马赫时显示,低于0.05马赫时消失

C.在PFD和MFD上都有显示

题型:实验题

化学教学评价加强对学生化学学习的质性评价,逐渐淡化量化评价。()

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