运用侯氏制碱法制得的纯碱中可能含有少量氯化钠．现取某种仅含有_爱下问搜题

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问题问答题

运用侯氏制碱法制得的纯碱中可能含有少量氯化钠．现取某种仅含有氯化钠一种杂质的纯碱样品23.4g全部溶解在350.0g水中，再加入氯化钡溶液166.0g，恰好完全反应生成碳酸钡沉淀．过滤出沉淀并干燥后，称得沉淀的质量为39.4g．

（1）求23.4g纯碱样品中碳酸钠的质量．

（2）求滤液中氯化钠的质量分数．

答案

设原混合物中碳酸钠的质量是x；生成的氯化钠的量为y

则有：Na₂CO₃+BaCl₂=BaCO₃↓+2NaCl

106 197 117

x 39.4 y

106：197=x：39.4 解得x=21.2g 197：117=39.4：y 解得y=23.4g

反应后溶液中溶质的质量分数为：

23.4-21.2+23.4

23.4+350+166-39.4

×100%=5.12%

答：（1）原混合物中碳酸钠的量是21.2g

（2）反应后溶质的质量分数为5.12%

完形填空

Andy was still travelling in Spain when he realized he had to eonfirm(确认) his flight home with the airline company. He was visiting Spain in order to   36  his Spanish. When he was speaking to people   37  he had no   38  understanding what they said.   39  , when he was speaking on the phone, he   40  had a problem. Andy   41  the airline. And the clerk confirmed that his plane was leaving at nine o’clock three days from that day. She   42 told Andy to be at the airport two hours   43  in order to check in his luggage and get a set.
Since he was   44  in three days, Andy didn’t   45 any time. He visited as many places as he could. He thought that it would probably be a while before he had enough money again. He wished he could   46  and spend a year in Spain.
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“No, sir. However, the next flight out will be three days from now. ”
Andy’s 53 of shock turned to one of 54   as he realized that now he could continue his   55 .

A．astonishment

D．hopelessness

单项选择题 A1型题

治疗脾肾虚寒，五更泄泻的方剂是（）

A.真人养脏汤

B.理中丸

C.四神丸

D.桃花汤

E.固精丸