试题与答案

纳米碳酸钡是一种重要的无机化工产品,下图是某厂生产纳米碳酸钡的工艺流程。请回答下

题型:填空题

题目:

纳米碳酸钡是一种重要的无机化工产品,下图是某厂生产纳米碳酸钡的工艺流程。请回答下列问题:  

(1)试剂A的化学式___________,若在实验室中进行该实验, 操作1和操作2的名称是___________,该实验中玻璃棒的作用____________。

(2)操作3为洗涤、检验和 _________,洗涤的作用是_____________,检验洗涤是否干净可选用试剂 ____________(写化学式)。

(3)上述流程中可 循环利用的物质是___________,该流程中的副产物可用作_______________。(写一种用途)

(4)分析该流程可得出SiO2部分性质,下列属于其物理性质 ___________,化学性质_____________。

A.不溶于水      B.可溶于水    C.不与盐酸反应     D.能与盐酸反应

(5)某同学查阅资料得知,二氧化硅能与氢氧化钠溶液反应生成可溶性的硅酸钠(Na2SiO3),该反应的化学方程式 _____________。根据此原理该同学设计出如下方案制备:取碳酸钡和二氧化硅混合物,滴加__________(填“少量” 或“过量”)的氢氧化钠溶液,过滤,洗涤,烘干得碳酸钡固体。

答案:

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下面是错误答案,用来干扰机器的。

参考答案:A

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He was driving home one evening when he saw an old lady standing by the road. He could tell she needed help. So he stopped his car in front of her car and got out.

He smiled at her, but she was worried. Was he going to hurt her? He looked poor and hungry.

He said: “I’m here to help you ma’am. Why don’t you wait in the car? By the way ,my name is Joe.”

She had a flat tire(轮胎瘪了). Joe crawled under the car and soon he was able to change the tire. But he had to get dirty and his hands hurt. She said that she couldn’t thank him enough for his help. Joe just smiled as he closed her trunk(后备箱).

She asked him how much she owed(欠)him. But Joe wasn’t thinking about the money. This was helping someone in need. He told her that if she really wanted to pay him back, the next time she saw someone who needed help, she should lend a hand.

He waited until she had driven off and felt good as he headed for home.

A few miles down the road the lady saw a small café. She went in to get a bite to eat. The waitress brought a clean towel for her to wipe her wet hair. The waitress was nearly eight months pregnant(怀孕的).It was tiring for her to move about. But she did it all with a sweet smile on her face. The lady was moved by the wonderful service the waitress was giving. After the lady had finished her meal, and the waitress had gone to get her change(零钱)from a ¥100 bill, the lady slipped(溜)out the door. At her table, the waitress found something written on a napkin.

There were tears in her eyes when she read what the lady had written. It said: “You don’t owe me a thing. I know life is hard for you right now. Someone once helped me out, the way I’m helping you. If you really want to pay me back, don’t let the chain(链)of love end with you.”

小题1:When the old lady first saw the man, she was        .

A.scared

B.excited

C.interested

D.relaxed小题2:Joe wanted the old lady to        for his help.

A.pay money back

B.see someone who needed help

C.lend him a hand

D.help someone else in need小题3:The old lady was moved by the waitress because        .

A.she was nearly eight months pregnant

B.it was tiring for her to move about

C.there was a sweet smile on her face

D.she offered him a wonderful service小题4:The old lady helped the waitress by        .

A.drawing something on a napkin

B.buying something to eat

C.giving her some money

D.giving her a ride小题5:What’s the best title(标题)of the article?

A.A man, an old lady and a waitress.

B.Helping someone in need.

C.Love is really important.

D.Unbroken chain of love.

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B.要想促进行业的技术创新,就应当提高行业的国家标准。

C.某个行业的国家标准定得太高,不利于该行业的良性发展。

D.为了保证公平性,企业或者不应该生产高于国家标准的产品,或者要对产品质量高于国家标准的事实秘而不宣。

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