（4分）（2012•巴中）如图所示，A～D是九年级化学常见物质．已_爱下问搜题

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问题推断题

（4分）（2012•巴中）如图所示，A～D是九年级化学常见物质．已知A为金属氧化物，C为大理石的主要成分，“→”表示物质之间存在的转化关系（部分生成物未标出）．请回答下列问题：

（1）D的俗名：　_________　（任填一种即可）

（2）B与D之间的化学反应属于　_________　反应（填基本反应类型）．

（3）写出A→B的化学方程式　_________　．

（4）写出B在生成、生活中的一种用途　_________　．

答案

（1）纯碱；（2）复分解；（3）CaO+H₂O=Ca（OH）₂；（4）中和酸性土壤等．

C为大理石的主要成分，可知C为碳酸钙，C高温分解生成A，而A为金属氧化物，故A为氧化钙；A与水反应后生成了B，B为氢氧化钙；根据B与D反应后的产物为碳酸钙和氢氧化钠，可以推断D是碳酸钠．

（1）D为碳酸钠，俗称纯碱或苏打．

（2）B为氢氧化钙，D为碳酸钠，两者反应生成碳酸钙沉淀和氢氧化钠，是两种化合物相互交换成分生成另外两种化合物的反应，属于复分解反应．

（3）A为氧化钙，与水反应生成氢氧化钙，反应的化学方程式为：CaO+H₂O=Ca（OH）₂．

（4）B为氢氧化钙，在生成、生活中可用于中和酸性土壤、作建筑材料等．

选择题

城市等级的划分标准通常是

A．城市占地规模

B．城市人口规模

C．城市化水平高低

D．城区建筑规模

完形填空

When I was in the 8th grade in Ohio, a girl named Helen in my class had a terrible accident. As she was   16  to the bus in order not to miss it, she slipped on the ice and fell under the back wheels of the bus. She   17  the accident but was paralyzed from the waist down. I went to see her, in my 13-year-old mind thinking that she wouldn’t live   18   from then on.
Over the years, I   19 and didn’t think much about Helen after that. Three years ago, in Florida, my oldest son was hit by a car while riding his bike,   20  a terrible brain injury. While I was looking after my son, a lady who said she was the hospital’s social worker called. It was a particularly tiring day. I burst into tears for no reason and rang   21 .
A short time 1ater, a beautiful woman, in a wheelchair,   22  into my son’s room with a box of 23 . After 16 years, I still   24  Helen. She smiled, handed me the tissues and hugged me. I told her who I was, and after we both went through the shock of that, she began to tell me about her life since we last saw each other. She married, had children and got her degree so that she smoothed the path for those people who were less   25  than her. She told me that if there was anything she could give me, it would be   26 .
Looking at this wonderful, giving person, I felt   27 . But I also felt the first hope I had since learning that my son was 28 . From this person that I thought would have no quality of life, I learned that where there is life, there is hope. My son miraculously   29  and we moved north, but I owe Helen   30 that I can never repay.

D．hospitalized

B．some tissues