题干

NA表示阿伏加德罗常数,下列说法正确的是

A:0.2 mol H2O2完全分解转移的电子数为0.4 NA

B:300 mL 2 mol/L蔗糖溶液中所含分子数为0.6 NA

C:在标准状况下,2.8 g N2和2.8 g CO所含电子数均为1.4 NA

D:在常温常压下,2.24 L SO2与O2混合气体中所含氧原子数为0.2 NA

上一题 下一题 0.0难度 选择题 更新时间:2018-11-04 09:17:31

答案(点此获取答案解析)

C

同类题2

阅读下面短文,掌握其大意,然后从每题所给的A、B、C、D四个选项中选出最佳答案

    Have you heard of STEM education? STEM 1 Science, Technology, Engineering and Mathematics. It means students can learn these 2subjects in one class. And they work on many projects to practice 3 they learn STEM education is very 4 in the US.

    Now more than 600 5 middle schools bring in STEM education, according to the paper, en. Beijing, Yuying School is one of them.

    The school 6 the course in May. It invited college teachers to teach more than 80 students programming, robotics and other interdisciplinary(跨学科}的) knowledge.

    The teaching style is quite 7, Once teachers finish teaching basie knowledge, studentes will practice it 8. For example, after learning about electrie circuits(电路),students are required to design one that could control three lights 9.They have many projects to improve their hands-on 10 as well. Once, they had a "smart home" model design project. All the students competed to design a 11 model and make it "smart" .Liu Tianyou, 12, with 12 teammates, used computer programs and sensors to finish it. "If you open the door of the house, the lights will 13 automatically, "he said. Their work won the third prize.

    The class, develops students' creativity as well. 14 Learning mechanies and programming in the class, Zhao Hngyi, 14, made a Lego robot himself in eight 15.From assembling(组装)to testing he finished it on his own. The robot can catch things and walk on certain tracks under orders. " It's cool to make my idea come to life," he said.