题干

在科学活动周中,某校兴趣小组同学在(培养中学生基本科学素养的化学实验教学研究)课题组老师的指导下,将课本“测定空气中氧气的含量”实验装置(如甲图)改进为新的实验装置(如乙图),改进后的实验装置相对于原装置,以下评价不恰当的是(  )

A:反应容器体积小,药品消耗少

B:装置简洁,减少了甲图装置中导管引起的误差

C:白磷比红磷着火点高,使用更安全

D:容器内径相等,易准确推算出空气中氧气的含量

上一题 下一题 0.0难度 选择题 更新时间:2019-06-13 11:49:10

答案(点此获取答案解析)

C

同类题5

阅读理解

    About 70 scientists were working on a very busy project. All of them felt really desperate due to the pressure of work and the demands of their boss but everyone was loyal to him and did not think of quitting their job.

    One day, one scientist came to his boss and told him, “Sir, I've promised to take my children to the exhibition going on in our township so I want to leave at 5:30 p. m.” His boss replied, “OK. You're permitted to leave the office early today.”

    The scientist started working. He continued his work after lunch. As usual, he got involved to such an extent that he looked at his watch only when he felt he was close to completion. The time was 8:30 p. m. suddenly he remembered his promise to the children. He looked for his boss but he was not there. Having told him in the morning himself, he closed everything and left for home. Deep within himself, he was feeling guilty for having disappointed his children. He reached home. The children were not there. His wife alone was sitting in the hall and reading magazines. The situation was explosive; any talk would boomerang on him. His wife asked him, “Would you like to have coffee or shall I straight away serve dinner if you are hungry?” The man replied, “If you would like to have coffee, I too will have but what about the children?” His wife replied, “You don't know? Your boss came here at 5:15 p. m. and has taken them to the exhibition.”

    What had really happened was the boss who gave him permission was observing him working seriously at 5:00 p. m. He thought to himself: this person will not leave the work, but he's promised to take his children to the exhibition. So he took the lead in taking them there. The boss does not have to do it every time. But once it's done, loyalty is established.

    That is why all the scientists at Thumba continued to work under their boss even though the stress was extraordinarily huge. By the way, can you boldly guess who the boss was? He was none other than the mastermind behind India's successful nuclear weapons program, Dr. APJ Abdul Kalam, former president of India.