题干

设NA为阿伏伽德罗常数,上述说法不正确的是(  )

①标准状况下,11.2L以任意比例混合的氮气和氧气所含的原子数为NA

②同温同压下,体积相同的氢气和氩气所含的分子数相等

③1L2mol/L的氯化镁溶液中含氯离子为4NA

④标准状况下22.4LH2O中分子数为NA

⑤32gO2和O3混合气体中含有原子数为2NA

A:③④⑤

B:①③④

C:④

D:③⑤

上一题 下一题 0.0难度 选择题 更新时间:2014-05-27 04:13:51

答案(点此获取答案解析)

C

同类题4

阅读理解

C

    Yang Hui was born in Longyan, Fujian. She grew up in a small village. She lost all her fingers and feet when she was three. She was badly burnt by accident when she went out with her grandparents. She couldn't walk and she seldom went out.

    The young girl had to learn to do everything. At first she wasn't able to use chopsticks. Her parents had to teach her for a long time. Thanks to her strong will(意志)to do everything by herself, she overcame those difficult times. Now she can look after herself. She also loves studying and she has finished the junior high school courses.

    About five years ago, Yang Hui saw someone make cross-stitch(十字绣)and she decided to learn to make it herself. As you can imagine, it's very difficult to make it without fingers. Yang Hui failed so many times. But she never gave up. And through many hours of practice, now she can use her arms to make good cross-stitch works and she is faster than other people. "One had to put great efforts into what she was doing." Yang Hui said.

    Now she is 21 years old and she is in hospital in Fujian. She continues making a 1.83-meter-long cross-stitch work with arms. She has no enough money for her operations(手术). Many kind-hearted people come to visit her and call on people to raise money for her.

    As for her future, Yang Hui said, "I hope to stand up and walk one day after operations. I want to make more money by selling cross-stitch works."

    If you want to know more about Yang Hui and help her, please call 13004982348.

(From Fuzhou News)