学习化学时会遇到许多“相等”或“不变”的关系,下列说法中错误的是( ) A.化学

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问题:

学习化学时会遇到许多“相等”或“不变”的关系,下列说法中错误的是(  )

A.化学反应前后元素的种类保持不变

B.原子中核内质子数与核外电子数一定相等

C.元素周期表中的原子序数等于该原子的核电荷数

D.化合物中元素化合价的正价与负价的数值一定相等

考点:质量守恒定律
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Kofi Annan says helping survivors of last week’ s earthquake and (1) in the Indian Ocean is (2) . The United Nations secretary- general says countries that have offered aid must (3) and provide it. The offers add up to around (4) dollars. United Nations officials say (5) of that is needed during the next six months. The concern about offers of international aid is (6) . For example, the earthquake in Barn, Iran, in (7) of 2003 killed more than (8) people. Countries and groups offered hundreds of millions of dollars (9) .The United Nations says it has (10) only about (11) dollars in aid received so far. Governments and organizations that offered help (12) that, however. On (13) Mr. Annan met with world leaders in Jakarta, Indonesia to discuss aid for (14) . The leaders discussed and (15) the idea of (16) owed by affected nations. But the leaders did not say they would do so. Some said that (17) to survivors would be more helpful. Representatives of (18) countries and international organizations attended the meeting in Jakarta. Officials say they will cooperate to develop (19) for the Indian Ocean and the (20) .

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诊断慢性前列腺炎时,前列腺镜检白细胞数为:()

A.0~5个/视野

B.>10个/视野

C.<10个/视野

D.5~10个/视野

E.满视野

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电子闪光灯色湿为()。

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怎样才能最大限度地保持种子生命力?

 

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竹节纱

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