问题 问答题

(12分)某研究型学习小组的同学在用浓硫酸处理费锌片时发现产生的气体具有刺激性气味,这种现象引起同学们的思考和研究。

【提出猜想】对产生的气体进行猜想:

猜想1:可能是H2;

猜想2:可能是SO2;

猜想3:可能是                 

【查阅资料】SO2易溶于水,能与NaOH溶液反应生成Na2SO3。

【实验方案】研究性学习小组的同学设计让图所示的装置进行研究(夹持仪器已省略,假设装置中的反应都进行完全)。

【问题讨论】

(1)如果装置A中没有明显现象,装置C中的现象为                  则猜想             成立。

(2)如果装置A中的现象为                           ,装置C中没有明显的现象则猜想                  成立。

(3)猜想3成立的实验现象是                                     

(4)装置B中浓硫酸的作用是                         

【思维拓展】

实验室中可以用氢氧化钠溶液吸收二氧化硫,反应的化学方程式是      

(2)小组内一同学又设计了判断SO2与NaOH溶液能否反应的装置(如图),实验时发现试管内液面上升,就得出SO2与NaOH溶液反应的结论,其同学认为这一结论不严谨,理由是                                。要得到科学严谨的结论,仍利用该装置,需做的对比实验是                    

答案

【提出猜想】H2和SO2

【问题讨论】

黑色粉末变红

溶液红色变浅(溶液红色变成无色也可以得分)

装置A中溶液红色变浅(溶液红色变成无色也可以得分)装置C中的黑色粉末变红色

干燥气体或吸收气体中的水蒸气

【思维拓展】

(1)2NaOH+SO2==Na2SO3+H2O

(2)SO2易溶于水,也能使液面上升;用等体积的水(或水)代替NaOH溶液进行实验

本题考查的是实验探究物质的组成成分,气体的干燥(除水),氢气还原氧化铜实验,碱的化学性质,书写化学方程式。

【提出猜想】根据元素守恒既反应前后元素种类不变,再从题意中提取有用信息,如可能同时产生两种无色气体,其中一种气体具有刺激性气味,即锌与硫酸反应生成的气体有三种猜想:猜想1:可能是H2;猜想2:可能是SO2;那么猜想3:可能是H2、SO2的混合物;

【问题讨论】由于氢气具有还原性,能与黑色的氧化铜反应生成红色的铜;二氧化硫易溶于水,和氢氧化钠反应,使滴有酚酞的氢氧化钠溶液颜色变浅;故

(1)如果装置A没有明显实验现象,装置C的现象为黑色粉末变红色,则该气体为氢气,猜想1成立;

(2)如果装置A中溶液红色变浅,装置C溶液无现象,则该气体为二氧化硫,猜想2成立;

(3)装置A中溶液红色变浅,装置C的现象为黑色粉末变红色,则气体为氢气和二氧化硫和混合气体,猜想3成立;

(4)浓硫酸具有吸水性,用来干燥气体。

【思维拓展】

(1)二氧化硫是酸性氧化物,和氢氧化钠反应生成亚硫酸钠和水,化学方程式为:SO2+2NaOH═Na2SO3+H2O;

(2)液面上升的原因是试管内气体减少,使试管内压强小于大气压强,但由于二氧化硫易溶于水,也能使液面上升,所以液面上升不能得出二氧化硫和氢氧化钠反应的结论;要得到科学严谨的结论,仍利用该装置,需做的对比实验,用等体积的水代替氢氧化钠溶液进行试验。

阅读理解

Every year, I tell my sons what I'd like for Mother's Day: a letter. Something written from the heart and offered freely rather than bought from a store and wrapped neatly. I don't always get my wish, nor do I always take the time to write to my own mother.

This year, my boys will be in two different states on Mother's Day. My mom and dad will be away together, and I'11 be driving home from a writer's workshop in Massachusetts. Thinking of the fact that many friends have already lost their mothers and that a few have lost children, I am deeply grateful that what separates us, for now at least, is merely distance. It won't always be so, and there is no way to prepare for that fact other than to appreciate the moment that is. My sons know that they can please me on Sunday with a phone call or an e-mail, and that is enough as I love their words. The very best gift they can possibly give me is their own happiness, the very fact of their busy. full and well-lived lives.

Still, knowing that my years of staying with my sons are over, I do Feel doleful. The truth is, I miss being the center of the universe to two little boys. And this holiday can be a bit painful.

I wonder if my own mother ever felt nostalgic ('VTIH WJ) for the passing of my childhood. I wonder if she realizes that she is still at the center of my universe and always has been. I don't often pause to think about it. but of course she is the one who has been right there, at my side from the moment I drew my very first breath. How to ever fully appreciate the woman whose presence and 1ove and example have shaped me into the adult I am? How to describe even a small part of the sharing. sacrificing. and support she has given me over the years?

小题1:The author mainly wants to tell us through the first paragraph that _____.

A.she hopes to get her son's letters very much

B.her sons don't often write to her on Mother's Day

C.Mother's Day is the very date that she longs for most

D.she is very sorry not to write to her mother often小题2:The author is deeply grateful for the present life because ____.

A.her sons don't live far away from her home

B.her parents and children are still alive

C.her parents are coming to her house to spend Mother's Day

D.her sons can please her on Sunday with a phone call小题3:According to the author ______

A.young people nowadays tend to ignore their parents

B.parents should not give their children too much freedom

C.children's happiness and success are the biggest comfort to parents

D.parents are not the center of their children's universe when children grow up小题4:What does the underlined word "doleful" in paragraph 3 mean?

A.sad

B.excited

C.guilty

D.proud小题5:What will the author probably tell about after the last paragraph?

A.She'll tell the reader about her mother's present situation.

B.She'll recall how her mother educated and cared for her.

C.She'll describe the reunion of her family on Mother's Day.

D.She'll tell the reader about her mother's achievements in her career.

名词解释