题干

青蒿素(C15H22O5)是一种治疗疟疾的药物,我国女科学家屠呦呦因发现青蒿素荣获诺贝尔奖.下列说法正确的是(   )

A:青蒿素中共含有42个原子

B:青蒿素中C,H,O三种元素的质量比是15:22:5

C:青蒿素的相对分子质量为282g

D:青蒿素中碳元素的质量分数最高

上一题 下一题 0.0难度 选择题 更新时间:2019-08-11 12:43:22

答案(点此获取答案解析)

D

同类题3

阅读材料,完成下列要求。

材料一:在过去很长一段时间里,对我国社会主要矛盾的论述均为“人民日益增长的物质文化需要同落后的社会生产之间的矛盾”。十九大报告提出,我国社会主要矛盾已经转化为“人民日益增长的美好生活需要和不平衡不充分的发展之间的矛盾”。

    目前人民对美好生活需要,已不仅对物质文化生活提出了更高要求,而且在民主、法治、公平、正义、安全、环境等方面的要求日益增长;我国社会生产力水平总体上显著提高,更突出矛盾是城乡、区域、收入分配等存在的不平衡不充分等问题,这已成为满足人民日益增长的美好生活需要的主要制约因素。我国社会主要矛盾发生的历史性新变化,关系全局、影响深远,这对党和国家工作提出了许多新要求,对于全面深化改革,实现共同富裕,对于决胜全面建成小康社会,实现中华民族伟大复兴的中国梦具有重要的理论指导和现实意义。

材料二:“一带一路”倡议是目前中国最高的国家级顶层战略,为欧亚大陆乃至世界经济发展带来了新的希望,开辟了新前景,注入了新动力。秉承“讲信修睦”、“协和万邦”的哲学理念,中国积极建设“丝绸之路经济带”。总结“丝绸之路”的发展历史,尽管丝路沿线各民族之间文明与发展程度相差很大,但它始终是一条和平之路。各国、各民族之间和平往来,相互尊重,做到和而不同,实现互利共赢。这对于今天我们建设“丝绸之路经济带”仍然具有十分重要的意义。

材料三:2017年是高考制度恢复四十周年。时代在变,高考也在变。招生制度从定向招生到“双轨制”再到实行“并轨”,从赋予高校自主招生权到探索招生和考试相对分离再到改变成绩是评价学生的唯一标准……四十年来,高考不断打破“一考定终身”“唯分取人”的窠臼,在探索中前进、在改革中发展。教育部决定,到2020年全面建立新高考制度,更好地发挥高考作为教育改革“指挥棒”的作用,进一步破解科学性、公平性等时代课题。因为实现中年民族伟大复兴,教育的地位和作用不可忽视。教育是国之计,也是民之生,影响当下,更关乎未来。

同类题5

阅读短文,根据短文内容补全表格中所缺的信息。(每空一词)

    Is it difficult for you to get up in the morning? Are you often late for work or school? Yes? Then a scientist called Mike has a special bed for you. His Bed will get you up in the morning! Here is how it works!

    The bed is connected to an alarm clock. First, the alarm clock rings. You have a few minutes to wake up. Next, a tape recorder in the bed plays soft music and then your girlfriend's beautiful voice comes, “Wake up, darling, please.” A few minutes later, loud music comes from the tape recorder. At the same time, you may hear the voice of your boss. Your boss shouts angrily, “ Wake up at once, or you'll be late!” If you don't get up after that, you'll be sorry! A plastic “foot” is in the bed. It kicks you in the head. Then the bed waits for a few more minutes. What! You're still in bed! Slowly the top of the bed rises higher and the foot of the bed goes lower. Finally, you fall off the bed and onto the floor. You are out of the bed and awake!

    Mike made his bed because he wanted to take part in a competition. Mike won one of the top prizes for his bed.

Title

A____Bed

____was it made by

A scientist called Mike

Why was it made

It's difficult for people to get up in the morning and Mike made it to take part in a____

____does it work

Step 1

The alarm clock wakes you up.

Step 2

A tape recorder plays____music and you will____your girlfriend's voice.

Step 3

Loud music together with your____voice will wake you up.

Step 4

A plastic “foot”____you in the head so____you can wake up.

Step 5

The bed makes you____off it and onto the floor and you have to wake up.