晶体硅是一种重要的非金属材料。制备纯硅的主要步骤如下: ①高温下用碳还原二氧化硅

题型:实验题

问题:

晶体硅是一种重要的非金属材料。制备纯硅的主要步骤如下:

①高温下用碳还原二氧化硅制得粗硅;

②粗硅与干燥HCl气体反应制得SiHCl3:Si+3HClSiHCl3+H2

③SiHCl3与过量H2在1000~1100℃反应制得纯硅。已知SiHCl3能与H2O剧烈反应,在空气中易自燃。

请回答下列问题:

(1)第①步制备粗硅的化学方程式为________________。

(2)粗硅与HCl反应完全后,经冷凝得到的SiHCl3(沸点33.0℃)中含有少量SiCl4(沸点57.6℃)和HCl(沸点 - 84.7℃),提纯SiHCl3的方法为_________________。

(3)用SiHCl3与过量H2反应制备纯硅的装置如图所示(热源及夹持装置均已略去):

①装置B中的试剂是_______,装置C中的烧瓶需要加热,其目的是________。

②装置D中发生反应的化学方程式为_____________________。

③为保证制备纯硅实验的成功,操作的关键是检查实验装置的气密性,控制好反应温度以及________。

考点:其他物质的制备(硫酸铜晶体、铁红等)单质硅
题型:实验题

医疗机构()。
各级疾病预防控制机构()。
国务院卫生行政部门()。

A.承担传染病监测、预测、流行病学调查、疫情报告以及其他预防控制工作

B.承担与医疗救治有关的传染病防治工作和责任区域内的传染病预防工作

C.在各自的职责范围内辅助传染病防治工作

D.领导本行政区域内的传染病防治工作

E.主管全国传染病防治及其监督管理工作

题型:实验题

Whether you will be a doctor or a police officer in the future, there’s a teacher in your life. They teach you and help you know who you are? Of course, you want to thank them.

Teachers’ Day is the perfect chance for students around the world to thank their teachers. The festival falls on different days in different countries.

In China, Teachers’ Day is on September 10. But in the US, teachers have a whole week to celebrate. Teacher Appreciation Week is in the first full week of May every year. Kids used to bring apples for their teachers because apples are healthy. Now, they bring gifts with pictures of apples, such as cups, picture frames(框架) and teddy bears. Some students also make DIY gifts for their teachers. During the week, school clubs often offer teachers a free breakfast of coffee and pastries.

The South Korean Teachers’ Day is on May 15. Many students offer flowers to their teachers. Another traditional gift is a card. Thousands of students prepare personalized cards and give them to their favorite teachers.

Although different countries have different Teachers’ Days, there’s one day for the whole world to honor teachers. On October 5 of every year, over 100 countries, such as Canada and the Philippines, express their thanks by celebrating World Teachers’ Day. UNESCO started the day in 1994. It wants to remind people of the importance of teaching.

Only you can make a card like this one

A fingerprint (指纹) card is a good gift on Teachers’ Day

You will need:

●Card

●Pen

●Colorful ink

1. Press your ink-covered finger on a clean card.

2. Use a pen to make your fingerprint into an animal or a robot.

3. Write words like “you are a wonderful teacher,” or “thank you for teaching me” on the card.

Some thank-you notes for great teachers

1. I am lucky to have the best teacher in this world. Wherever I may go in my life, I will always remember that I had an excellent guide...You.

2. You are not only my teacher; you are my friend. I will always be grateful to you for your support and kindness.

小题1:According to the passage, apples used to be a good choice of gifts for Teachers’ Day because     .

A.students want to wish their teacher good health

B.apples are in season on Teachers’ Day

C.students want to wish their teacher success

D.apples are sweet and cheap小题2:More than 100 countries celebrate World Teacher’s Day on         .

A.October 5

B.May 15

C.September 10

D.May 5小题3:During the Teacher Appreciation Week in the US, school clubs often provide teachers with_____________.

A.a movie ticket

B.a free breakfast

C.a beautiful card

D.a free trip小题4:The part of “Only you can make a card like this one” is to tell the readers           .

A.where to order a beautiful card

B.how to make a meaningful DIY card

C.what kind of gift is best for teachers

D.how to order a teacher’s card online

题型:实验题

关于Fallot四联症,下列哪项是正确的()

A.肺动脉狭窄、右心室肥厚、室间隔缺损、主动脉骑跨

B.肺动脉狭窄、右心室肥厚、室间隔缺损、动脉导管未闭

C.右心室增大、室间隔缺损、主动脉骑跨、动脉导管未闭

D.肺动脉狭窄、右心房增大、室间隔缺损、主动脉骑跨

E.肺动脉狭窄、左心房增大、室间隔缺损、主动脉骑跨

题型:实验题

某提单的收货人栏填写“凭指定(Toorder)”字样,此提单是()

A.记名提单

B.不记名提单

C.指示提单

D.舱面提单

题型:实验题

良性与恶性肿瘤的声像图鉴别,下列哪项是最全面的 ( )

A.边界光滑,整齐与否

B.外形是否为圆形或椭圆形

C.内部低回声或回声增强

D.后方回声增强或衰减

E.边界回声、外形、内部回声综合分析

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