问题 填空题

干粉灭火器 内装有碳酸氢钠固体.灭火时,干粉喷出盖住燃烧的物体,并受热变成碳酸钠、水和二氧化碳,使火焰熄灭.请写出该反应的化学方程式,并指出反应的基本类型.______.

答案

碳酸氢钠在受热的条件下分解生成碳酸钠、水和二氧化碳,该反应由一种物质反应生成三种物质,符合分解反应的概念,属于分解反应,

故答案为:2NaHCO3

 加热 
.
 
Na2CO3+CO2↑+H2O    分解反应.

单项选择题 共用题干题
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When I was 15, I had an enemy, a girl who liked to point out my short-comings(缺点). Week by week her list grew. I was skinny(瘦的), I talked too loud, I was too proud, and so on. I put up with(忍受)her as long as I could. At last, I ran to my father in tears and anger. He listened to my outburst quietly. They he asked, “Are the things she says the true or not?”True? I wanted to know how to strike back. What did truth have to do with it?

“Mary, didn’t you ever wonder what you are really like? Well, you now have that girl’s opinion. ”Go and make a list of every thing she said and mark the points that are true. You needn’t pay attention to the other things she said.

I did as he told me and discovered to my surprise that about half the things are true. Some of them I couldn’t change(like being skinny), but a good number I could and suddenly wanted to change. For the time in my life I began to get a quiet clear picture of myself.

I brought the list back to Daddy, but he wouldn’t take it.“That’s just for you,”he said.“You know better than any else the truth about yourself, once you hear it. But you’ve got to learn to listen, not close your ears in anger or hurt. When someone says something about you, you’ll know if it’s true or not. If it is ,you’ll find it will echo(共鸣)inside you.”

“I still don’t think it very nice of her to talk about me in front of everybody.”

“Mary, there is one way you could stop others talking about you ever again, and criticizing(批评) you—just say nothing and do nothing. But then, if you do that, you’d find you were nothing. You wouldn’t like that now, would you?”“No, I admitted(承认)”

小题1:One day the writer ran to her father in tears and anger because__________.

A.she found she talked too much.

B.she found she was too proud.

C.her classmates were not friendly to her.

D.a girl pointed out many of her shortcomings.小题2:The writer’s father asked her ____________.

A.to pay attention to all that her“enemy”said about her.

B.not to pay attention to what her“enemy”said about her.

C.to pay attention only to the points that were true about her.

D.to pay attention only to the points that were not true about her.小题3:The writer found that___________.

A.about half the things her“enemy”said were true.

B.most of the things her“enemy”said were true.

C.few of the things her“enemy”said were true.

D.none of the things her“enemy”said were true.小题4:The writer’s father thinks__________.

A.if one says nothing and does nothing, people will praise him.

B.one should not do anything because others will talk about him.

C.it is not good to talk about others.

D.everyone is talked about by others.