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海水是盐的丰富宝藏，海水的咸、涩味感，是由于海水中除含有食盐以外，还含有多中盐类物质．已知海水中含有丰富的Na+、K+、Ca2+、Mg2+、Cl-、SO42-、等离子，通过晾晒海水，可以蒸发除去其水分，得到含有较多杂质的氯化钠晶体--粗盐．

你觉得粗盐晶体中的杂质是指什么物质，请你写出它们的化学式：______．

如果请你检测粗盐中是否含有SO42-，你的做法是：______．

答案

（1）可以将四种阳离子和两种阴离子两两组合形成物质，列如下：

  Na+ K+ Ca2+ Mg2+Cl-  SO42-
 Na+ ______ ______ ____ ______ NaCl Na2SO4
 K+ _____ _______ ______ ______ KCl K2SO4
 Ca2+ _________ ______ ______ _____ CaCl2 CaSO4
 Mg2+ ____ ______ ______ _____ MgCl2 MgCl2
Cl-  

 NaCl

 KCl CaCl2 MgCl2 ______ ______
 SO42-Na2SO4  K2SO4CaSO4 MgCl2 _______ _____
根据上表可知，粗盐晶体中的杂质是：Na2SO4、KCl、K2SO4、CaCl2、MgCl2、MgSO4（硫酸钙微溶于水，所以不能大量存在于溶液中）．

（2）要检验硫酸根应该用含钡离子的化合物与硫酸根形成硫酸钡沉淀，与钡离子形成物质的阴离子又不能形成沉淀，加入的硝酸是为了排除碳酸根离子的干扰，故答案为：取少量粗盐溶于蒸馏水，再滴入2～3滴Ba（NO3）2溶液，如有白色沉淀，再加几滴稀硝酸，若沉淀不溶解，就说明精盐中含有SO42-离子．

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     Many a young person tells me he wants to be a writer. I always   1   such people, but I also explain that
there's a big   2   between "being a writer" and"writing".
     In most cases these individuals are dreaming of wealth and fame,   3   the long hours spent alone   4   .
"You've got to want to write," I say to them,"not want to be a writer."
     The   5   is that writing is a lonely, private and poor-paying affair. For every writer kissed by   6   there are
thousands more whose longing is   7   rewarded. When I   8   a 20-year career in the U.S. Coast Guard to
become a freehand writer, I had no prospects (前景) at all. What I   9   was a friend who found me a room in
a New York apartment building. It didn't   10   matter that it was cold and had no bathroom. I immediately
bought a (an)  11  manual typewriter and  12  a genuine writer.
     After a year or so,   13   , I still hadn't gotten a break and began to   14   myself. It was so hard to sell a
story that I   15   made enough to eat. But I knew I   16   write.
      I had dreamed about it   17   . I wasn't going to be one of those people who die  18       
     "What if?" I would keep putting my dream to the  19  even though it meant living with uncertainty and fear
of failure. This is the Shadow Land of  20 , and anyone with a dream must learn to live there.
( )1. A. advise       
( )2. A. step         
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问答题 简答题

2001年9月11日深夜，牛某伙同孙某窜至×市某烟酒商店。孙某在外面望风，牛某用断线钳掐断商店窗户上的钢筋，进入屋内，盗窃现金2000余元、名酒、香烟等物品，共计价值5000多元。

对孙某该如何处罚？
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