除去下列物质中的杂质（括号内为杂质），完全正确的是物质选用_爱下问搜题

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问题选择题

除去下列物质中的杂质（括号内为杂质），完全正确的是

	物质	选用试剂	操作方法
A	Cu（CuO）	O₂	通入氧气并加热
B	CaO（CaCO₃）	——	高温煅烧
C	H₂（H₂O）	稀硫酸	洗气
D	KCl（K₂CO₃）	盐酸	加入足量盐酸充分反应后，蒸发结晶

答案

BD

题目分析：A通入氧气并加热会将单质铜变为氧化铜；B高温煅烧，碳酸钙会分解为氧化钙和二氧化碳，煅烧后只含有氧化钙；C 干燥气体使用的是浓硫酸，具有吸水性，稀硫酸没有吸水性，不可以用作干燥剂；D 盐酸和碳酸钾反应生成氯化钾、水和二氧化碳，蒸发结晶后二氧化碳和氯化氢皆挥发，只剩下氯化钾。

点评：对于常见化学物质的除杂问题属于中考的常考点，选择填空均可出题，考察形式较为灵活，注意积累总结。

单项选择题

关于碘缺乏病严重程度比较，下列哪组不对？（）

A．山区＞平原

B．内陆＞沿海

C．农村＞城市

D．河谷冲刷带＞平原

E．河谷冲刷带＜平原

完形填空

Coin confusion
Rachel looked through troubled eyes at her sister and said, "I wouldn't have thought Eric would be a thief." Her sister Sarah replied, "Whoa, that's a      accusation to make against your best friend!"
Rachel remembered two days ago when she had brought out her coin collection for Eric to     . At the end of that day, Rachel's mother asked her to do her a favor, so she asked her friend," Is it okay if I leave you for a few minutes?" Eric said, "Go ahead. I’ll clean up here,"      at the piles of coins on the floor.
When Rachel returned, it never occurred to her to     her coins until two days later that she realized some quarters were      .
Sarah said, "Why don't you just ask him?"
"Ask him what? Hey, best friend, did you       my coin collection?" Rachel thought for a moment,        if that would be a good idea. The theft of her collection left her with a feeling of        "How could I have misjudged my friend's       ?"
The next day Rachel went to Eric's house. Eric was acting funny sort of nervous, like he couldn't be       . In fact, Rachel thought Eric acted like someone with a secret. Anger blossomed as Rachel watched Eric pretend to be kind,      Eric had obviously stolen from her. Rachel finally could not stand it anymore and stood up. Suddenly, Eric     ,"I can't stand it anymore!" Rachel was astonished at hearing her own      burst forth from her friend! Instead of sounding     , Eric sounded excited. He pulled something from underneath the chair.
"Go to open it! I was going to wait until your birthday, but I can't wait." Slowly, Rachel lifted the top of the     . Laid out in front of her were all of the quarters from her coin collection. Each quarter was in its own      in a new collection case. Each quarter shone like it was new.
Rachel felt      rush over her neck and ears. She said     , "Thank you! This means... a great deal to me." She was grateful that Eric had cut her      before she said something she would     . Eric was exactly the type of person she wanted as a friend!

B．unwillingly