题干

青石棉(cricidolite)是世界卫生组织确认的一种致癌物质。它的化学式为:Na2Fe5Si8O22(OH)2,青石棉用稀硝酸溶液处理时,还原产物只有NO,下列说法正确的是

A:青石棉的化学组成用氧化物的形式可表示为:Na2O·5FeO·8SiO2·H2O

B:该反应中氧化产物与还原产物的物质的量之比为3︰1

C:青石棉是一种易燃品,且易溶于水

D:适量Na2Fe5Si8O22(OH)2能完全溶于足量硝酸中,得到澄清透明溶液

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答案(点此获取答案解析)

B

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    My wife Pat and I were having drinks outside our home, The weather was unusually1for March in Mississippi, There was barely any breeze, After we finished the second cup, flashes of2danced across the sky. When the first drops of rain drove us3 the phone rang.Pat's face4on that gray and hot day. It was our son, David, a helicopter pilot who5in the US Air Force in South Korea. David intended to sound6but we recognized the sign of homesickness from his voice7the power of conversation made us feel8until a crash shook the windows.

    David wondered what it was,“Just thunder,”Pat said.

    There were several seconds of silence,“David”,I asked, “are yo9there?”

    “Yes…apart from the two of you, do you know what else I10most? Thunder, We have rain, wind, and11here, but it never thunders, Remember? Dad, when I was a kid, you laughed me out of fear of thunder? I wish I were there to12with you now.”

    “Yes…”I said, trying to13my tears, On hanging up the phone, I told Pat,“I'm going to record our son some 14”“Bob, the neighbors will think you're crazy.”

    “David won't,” I said and went outside with a recorder, Later I15the tape to David with a single line:A16gift.

    David called again, “Dad,”he said,“you won't believe that some friends and I had a thunder party where we realized we were listening to the sounds of 17 Thanks, Dad! It was really a special present,” While David was in Korea, we found ourselves 18thunderstorms.19feeling blue, we regarded the thunder as special which let us know that wherever we might be, we were 20together as a family.