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问题 问答题

某化工有限公司生成的硝酸铵产品包装袋上的说明如图所示，

（1）若你来计算硝酸铵的含氮量，你的方法是______．

（2）请你判断该化工有限公司生成的硝酸铵是纯净物还是混合物？______

（3）该化工有限公司生产一袋硝酸铵产品中氮元素的质量是______；多少kg尿素[CO（NH2）2]与一袋硝酸铵产品中含氮元素质量相同？（写出计算过程，结果精确到0.1%）

答案

（1）根据化学式及元素质量分数的计算来计算，故答案为：根据化学式判断原子个数，用原子个数和原子量来计算，NH4NO3中有2个N原子，可列式

2×14
2×14+1×4+16×3
×100%=
28
80
×100%=35%；

（2）因为35%＞34%，故该硝酸铵样品是混合物．

（3）由标签说明可知一袋样品是50kg，含氮量为34%，因此含氮元素质量为50kg×34%=17kg；尿素中氮元素的质量分数为：

2×14
60
×100%=46.7%，含氮量为17kg，需要尿素的质量为：
17kg
46.7%
=36.4kg

故答案为：

（1）

Ar(N)×2
Mr(NH4NO3)
×100%=
2×14
80
×100%=35%．

（2）混合物

（3）17kg； 36.4kg

完形填空
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       In one way of thinking,  failure is part of life. In   1   way, failure may be a way towards success.
The "Spider-story" is often   2  .Robert Bruce , leader of the Scots(苏格兰) in the 13 th century, was
hiding in a cave（洞穴）from the English. He watched a spider   3   a web. The spider tried to reach
across a rough(粗糙的)   4   in the rock. He tried six times. On the   5   time he made it and went on
to make his web. Bruce is said to have been encouraged by this and to have gone on to  7    the English .
Edison ,  the inventor of the light bulb,  made   6    models that failed before he found the right way to
make one. Once he was asked   8   he kept on trying to make a new type of battery when he had failed
so often, he replied, “Failure? I have   10   failure. Now I know 50,000 ways it won't    9    
       The important thing to keep in mind about failure is that it's a part of life. Learn to "live with yourself"
even though you may have failed．
( )1. A. other    
( )2. A. told      
( )3. A. to make  
( )4. A. room      
( )5. A. tenth    
( )6. A. save      
( )7. A. hundred  
( )8. A. why      
( )9. A. not      
( )10.A. do        		B. another
B. said
B. made
B. house      
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B. make        		C. first
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选择题

乙酸蒸气能形成二聚分子2CH3COOH(g) （CH3COOH）2 (g)   Δ H<0 ，欲测定单体乙酸的相对分子质量，应采用的条件是（   ）

A．高温低压

B．低温高压

C．低温低压

D．高温高压
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