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问题 选择题

下列说法正确的是                    

A．6.2g氧化钠和7.8g过氧化钠混合物中所含有的离子数目为0.7×6.02×1023

B．1L 0.1mol•L-1Na2CO3溶液中，CO32-的数目小于0.1×6.02×1023

C．6.4 gSO2在一定条件下与足量氧气充分反应后失去的电子数目为0.2×6.02×1023

D．标准状况下，22.4L CH4和CHCl3的混合物所含有的分子数目为6.02×1023

答案

答案：B

本题考查阿佛加德罗常数与微粒数的关系；6.2gNa2O中含有离子共0.3mol，7.8gNa2O2中含有离子共0.3mol，混合物所含有离子数为0.6×6.02×1023，A错误；Na2CO3为强碱弱酸盐，会发生水解，CO32-+H2OHCO3-+OH-，所以溶液中CO32-的数目小于0.1×6.02×1023，B正确；6.4 gSO2与氧气反应是可逆反应，SO2在反应后失去的电子数小于0.2×6.02×1023，C错误；标准状况下，CHCl3为液态，D错误。

以“尊王攘夷”为号召，成为春秋时期第一个霸主的是（    ）

A．楚庄王

B．晋文公

C．齐桓公

D．秦孝公
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单项选择题

Government officials reported three new cases of mad cow, bringing the total so far this year to 99. Last year, France recorded just 31 cases of the mad cow disease. The rising numbers are in part (1) a new testing program that focuses on cows that are most (2) . That program has (3) 39 cases. But still 60 new cases were identified in the usual way, (4) were found in 1999. Many scientists (5) that this year, five years after safety precautions were (6) , the number of cases would be (7) .

The rise in cases has (8) some scientists to question whether the disease can be transmitted in ways not yet understood. Scientists are still (9) the disease, first recognized in cows in 1986.

It appears that it is not caused by a bacteria, virus or fungus, but (10) infectious particles called prion, perhaps (11) a virus or other agent. The disease kills cells in the brain, (12) it spongy and full of holes.

France has taken more steps to (13) safety than most European countries, (14) refusing to take English beef (15) the European Union. But some scientists believe that France has not been (16) in imposing the ban on feed that (17) animal pans.

Some French officials hope that the sudden interest in mad cow disease will mean that French consumers will become educated about it, thereby recognizing that French beef is actually (18) controlled. Every cow is given a passport at birth, and extensive information about its parentage and (19) it was raised must be (20) to any slaughterhouse. When a diseased animal is found, the entire herd is destroyed.

6（）

A. put to place

B. put a place

C. put in place

D. put in the place
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