问题 实验题

(9分)硬水中含有较多的可溶性的钙、镁的化合物,其中钙的化合物为Ca(HCO3)2,受热易分解,对其加热生成水和大量的气体,还有一种难溶性的物质。该固体物质是水垢的成分之一。

(1)【提出问题】探究Ca(HCO3)2受热分解的另外两种生成物。

(2)【猜想】①小刚认为生成物中的气体可能是二氧化碳。

②你认为生成物中的固体物质可能是              

(3)【设计实验方案】小刚和你的实验方案

猜想实验操作实验现象结论
   
   
(4)【归纳和表达】写出Ca(HCO3)2受热分解的化学方程式:

                                                   

答案

(2)碳酸钙或CaCO3

(3)

猜想实验操作实验现象结论
将生成气体通入装有少量澄清石灰水的试管石灰水变浑浊生成物中的气体是二氧化碳
取少量生成的白色固体物质于试管中,向其中滴入适量稀盐酸固体溶解,冒气泡固体物质是

碳酸钙

(答案合理给分)

(4)Ca(HCO3)2CaCO3 + H2O+ CO2↑(CaCO3旁写↓也可以)

:(2)②由题意可知,生成物中固体物质是水垢的成分之一,故判断是CaCO3

(3)①因二氧化碳与石灰水反应的化学方程式为Ca(OH)2+CO2=CaCO3↓+H2O,有沉淀生成,故石灰水变浑浊,即可判断该气体是CO2

②因碳酸钙与盐酸反应的化学方程式为CaCO3+2HCl=CaCl2+H2O+CO2↑,二氧化碳与石灰水反应的化学方程式为Ca(OH)2+CO2=CaCO3↓+H2O,有沉淀生成,故石灰水变浑浊,由此可判断该固体为CaCO3

猜想实验操作实验现象结论
将生成气体通入装有少量澄清石灰水的试管石灰水变浑浊生成物中的气体是二氧化碳
取少量生成的白色固体物质于试管中,向其中滴入适量稀盐酸固体溶解,冒气泡固体物质是

碳酸钙

(4)Ca(HCO3)2CaCO3 + H2O+ CO2

阅读理解

阅读理解。

     Jackie Joyner-Kersee had a serious asthma attack while running a race at the 1994 U. S. Olympic Festival.

     "I wasn't afraid of running; I was afraid I might die," said Joyner-Kersee. "I said 'Don't be afraid. . . just

hold on."

     So, what is asthma? It's a health condition that causes difficulty in breathing. Although it comes and goes,

once you have asthma, you have it for a long time. Different treatments are used for asthma. There are very

strong drugs that can be taken for a long time with few side effects. Today, even people with serious asthma

can take part in sports.

     Joyner-Kersee has had problems with asthma for many years. She said, "I didn't have this as a little girl.

It wasn't until I went to California that I noticed it, and then I didn't want to accept it. When I start feeling

good, I stop taking the medicine. It will be all right. . . . I hope. "

     The race was supposed to start at.5:35 p. m. At 5:00, she began to have trouble breathing. She was

given a breathing test and treatment by a doctor. She said she thought about not running. She was out of

breath.

     "It's just hard running with asthma," she said. "When I experienced this in practice. I couldn't breathe.

It was really hard for me. " She said the problem with asthma is that you don't know when it will happen.

She was fine when she arrived at the stadium. The breathing treatment helped her. Joyner-Kersee's experience

shows that medical treatment is important. First, if you think you have asthma, see a doctor. Asthma drugs

can protect your lungs. Second, pay attention to your health. Tell your doctor immediately if you wake up and

have trouble breathing. This means the condition is getting worse. Many people don't want to be known to

have asthma, and then they must go to the hospital.

     Most importantly, remember that with asthma, you can have a normal life. You can even win an Olympic

gold medal.

1. Did Jackie Joyner-Kersee run at the 1994 U. S. Olympic Festival? 

   _________________________________________________________________

2. What is asthma? 

   _________________________________________________________________

3. When did Joyner-Kersee first find she had asthma?

   _________________________________________________________________

4. How can you tell your asthma is getting worse?

   __________________________________________________________________

5. What do you think is the writer's purpose of writing the passage? 

   __________________________________________________________________

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