试题与答案

2001年诺贝尔化学奖授予美国化学家诺尔斯博士和日本化学家野依良治教授,以表彰他

题型:问答题

题目:

2001年诺贝尔化学奖授予美国化学家诺尔斯博士和日本化学家野依良治教授,以表彰他们对催化不对称合成重大贡献.环氧化(R)-丙烯醇(化学式为C3H6O2)是沙普利斯应用不对称合成技术合成的一种重要物质,该物质可用于生产一种治疗心脏病的药物.计算:

(1)C3H6O2中碳、氢、氧三种元素的质量比;

(2)该物质中氧元素的质量分数.(计算结果保留一位小数)

答案:

(1)C3H6O2中碳、氢、氧三种元素的质量比为:12×3:1×6:16×2═18:3:16,

答:碳、氢、氧三种元素的质量比为18:3:16.

(2)氧元素的质量分数为:

16×2
12×3+1×6+16×2
×100%═43.2%,

答:该物质中氧元素的质量分数43.2%.

试题推荐
题型:多项选择题 案例分析题

病历摘要:患者男性,60岁,有糖尿病和高血压史8年。近半月来出现劳累性心前区闷痛,每此持续5分钟,常规心电图未见异常。PE:BP170/100mmHg,心率85次/分,心尖部可闻及3/6级收缩期吹风样杂音。

典型心绞痛的特点是()。

A.胸骨后心前区,手掌样大小

B.烧灼感

C.压迫紧缩感

D.常发生在夜间

E.常发生在一天劳累之后

F.持续3~5分钟;常由情绪激动或体力活动诱发

查看答案
题型:填空题

Before you speak to any audience, you should learn as much about its members as possible. Only in that way can you best adapt the level of your language and the content of your talk to your listeners.

41. Speaking to someone you know well.__________

Where are you likely to speak Certainly, in this class you’ll give several talks, and since you know most, if not all, of the students, you should face no major problems in adapting your approach to them. Another speaking possibility exists in your workplace.

A third speaking possibility exists in any organization (social, cultural, athletic, and so on) that you belong to. You may be asked to speak at the next meeting or at the annual banquet. Here again, you know the people involved, their background, their education level, and their attitudes, and that’s a tremendous advantage for you. Since we’re upbeat and positive in this course, we’ll assume that you’ve given successful talks under all three circumstances, and with this course under your belt, you can do it again. Since good speakers are hard to find and word about them travels fast, suppose that one day you get an invitation to speak to an organization in which you don’t know a soul. What do you do now If you feel able to handle the topic you’re asked to speak on, accept this rare challenge. Here’s where audience analysis comes into play. Be sure to ask the person who invited you for information on the members, information that encompasses a broad spectrum, such as in the following areas.

42. How old are your listeners

43. Sex composition of your listeners.

44. Interest in topic.__________

45. Interests or hobbies of the listeners.__________

[A] If you’re invited to speak to a women’s or men’s organization, you know the answer to this question at once. Quite often, however, audiences are mixed fairly evenly, although at times one sex may predominate.

[B] Do members of your prospective audience spend evenings watching TV movies and drinking beer at a local tavern, or do they read the Harvard Classics and attend concerts of Beethoven and Mozart Do they play bingo and 21, or do they pursue the questions the intriguing intricacies of contract bridge and chess Answers to these questions can help you choose the most appropriate material and language for your audience. Your choices can be crucial in determining the success or failure of your presentation.

[C] Are the members recent college graduates, senior citizens, or business executives in midcareer Just remember, age exerts a powerful impact on people’s attitudes, values and motivations.

[D] For example, your department manager may ask you to explain and demonstrate a procedure to some fellow employee. Or she may select you to address your department on behalf of the local blood donor drive. In both speech situations—in class and on the job—you’re familiar with your audience; you speak their language; you have things in common with them.

[E] Are you aware of the educational background of your audience How many of them have doctoral degrees, master degrees or bachelor degrees This will decide what kind of language you should adopt and how much they can understand.

[F] Are the members of the organization interested in the topic or are they required to attend regardless of their interest If the latter is true, what types of material will most likely pique their curiosity

41()

查看答案
微信公众账号搜索答案