某同学用下面装置实现铜与浓、稀硝酸反应,过程如下 Ⅰ.取一段铜丝,用稀硫酸除去铜

题型:实验题

问题:

某同学用下面装置实现铜与浓、稀硝酸反应,过程如下

Ⅰ. 取一段铜丝,用稀硫酸除去铜锈[主要成分是Cu2(OH)2CO3]。

Ⅱ.将洗涤后的铜丝做成匝数较多的螺旋状。

Ⅲ.按下图所示连接仪器、检查气密性、装入化学试剂。

(1)过程I发生反应的离子方程式是____________________________________。

(2)过程Ⅱ将铜丝做成螺旋状的目的是____________________________________。

(3)过程Ⅲ的后续操作如下:

①为使浓硝酸与铜丝接触.操作是______________________。当红棕色气体较多时,轻抽注射器使反应停止,关闭a,取下注射器。

②换入另一注射器后,打开b和分液漏斗活塞,玻璃管充满稀硝酸时,关闭b打开a,可见无色气体产生。稀硝酸充满玻璃管的实验目的是________________________________________________________________。

(4)已知:NO+NO2+2NaOH==2NaNO2+H2O;2NO2+2NaOH==NaNO3+NaNO2+H2O,NO和NO2的混合气体的组成可表示为NOx。将该混合气体通入NaOH溶液被完全吸收时,x的取值范围应为______________。

考点:设计实验方案及探究实验单质铜(浓、稀)硝酸
题型:实验题

下列疾病两肺满布干啰音的是()。

A.支气管异物

B.支气管肺炎

C.支气管扩张

D.支气管哮喘

E.支气管肺癌

题型:实验题

阅读理解

     The seventh game of any playoff series is always special, win or lose.It always has an edgeofyourseat,

heartinyourthroat intensity unlike any others.One play, one shot or one save may make all the difference.

      But there are other things that make our games and sports so special.

      For example, where we play our sports is often one of the best things about the games.Think of it:

What is as perfect as a fresh sheet of ice after the Zamboni machine (赞博尼磨冰机)has made its final

pass and left the surface as smooth as glass? Or a swimming pool on a summer morning, clear and calm,

before the first swimmer has broken the water?

      To me a freshly mowed and lined soccer field is as beautiful as any painting.So is a golf course in the

early morning, or in the evening when the sun is setting.

      The stuff we play with is wonderful, too.Is there anything that feels as good in your hand as a brandnew baseball? Or a nice leather football? Grab hold of either, and you just have to play a game of catch.

      The clothes are good too.Sports uniforms are much more colorful and comfortable than regular clothes.Maybe that's why so many kids stay in their sports uniforms long after their games are over.

      No shoes feel better on my feet than my golf shoes.Maybe that's because I know I am going to have

fun whenever I put them on.

     We talk so much about winning in sports.But if you are the kind of kid who is happy only when their

team wins, then sports will let you down.After all, no team or player wins all the time.

      But if you can learn to enjoy the parts of sports that have nothing to do with winning or losing-the feel

of a favorite bat or a stick in your hand, or how your heart beats when you put on your uniform and run

onto the field-then sports will always be fun, whether you win or lose.

1. Which of the following words is closest in meaning to the phrases "edgeofyourseat, 

    heartinyourthroat"  in Para.1?

A. Uncertain.        

B. Scared.

C. Nervous.          

D. Enthusiastic.

2. According to the writer, people are advised________.

A. not to play a game of catch

B. to wear sports uniforms long

C. not to talk about winning in sports

D. to have fun in sports

3. Sports uniforms, as well as sports shoes, are mentioned in the text________.

A. as an example of the special feeling of sports

B. as comfortable sportswear

C. as particular desire of children

D. as the most favorite of sportsmen

4. Which would be the best title for the passage?

A. Whether You Win or Lose  

B. Many Joys of Sports

C. Winning in Sports  

D. Games and Sports

题型:实验题

配置混凝土用砂,要求应尽量采用()的砂

A.空隙率较大、总表面积小

B.总表面积大、空隙率较小

C.总表面积和空隙率均较大

D.空隙率和总表面积均较小

题型:实验题

设在沿船长方向的舭部,作用是()。

A.保证船体总纵强度

B.增强舭部局部强度

C.减轻横摇

D.减轻纵摇

题型:实验题

简述正确使用盈亏分界点分析法必须具备的两个条件?

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