题干

下图为某反应的部分微观示意图,其中不同的球代表不同元素的原子。下列说法正确的是(   )

A:该反应属于置换反应

B:参加反应的两种分子个数比为1∶1

C:1个X分子中有3个原子

D:各元素的化合价在反应前后均未改变

上一题 下一题 0.0难度 选择题 更新时间:2019-04-07 10:02:39

答案(点此获取答案解析)

C

同类题2

根据短文内容,完成下列任务。

    China has its first Nobel Prize in Science. And the winner, 84-year-old Chinese scientist Tu Youyou, also became the first Chinese woman to win the Nobel Prize. She won the 2015 Nobel Prize in Physiology or Medicine with William C. Campbell, an Irish-born researcher, and Satoshi Omura of Japan. The three winners will share the prize of 8 million Swedish crowns ($920,000).

    Half of the Prize was given to William C. Campbell and Satoshi Omura for their new treatment against illness caused by roundworm parasites (寄生虫). Tu Youyou won the other half of the Prize for developing a medicine, Artemisinin(青蒿素), which can help people fight malaria(疟疾). More than 240 million people in Africa have benefited from the treatment, according to the WHO (World Health Organization), and more than 1.5 million lives have been saved since 2000, thanks to the medicine.

    Tu Youyou started her research in 1969 when she was chosen as the director of a government project to find anti-malaria medicines. She and her workmates studied ancient Chinese medicine books and many different traditional treatments. They did nearly 200 experiments before they finally succeeded in getting the material Qinghaosu, later known as Artemisinin, in the 1970s. This medicine became the standard treatment for malaria in the WHO's list of important medicines.

    Premier Li Keqiang congratulated Tu for winning the Prize. He said, "Tu's winning the prize shows China's progress in scientific and technological field, and marks a great contribution of Traditional Chinese Medicine (TCM) to human health."

    Although it's a late honor for Tu and the world's recognition of Traditional Chinese Medicine, Tu's winning the first Nobel Prize in Physiology or Medicine makes Chinese scientists encouraged and confident to achieve more success in the future.