首页
登录
职称英语
About a century ago, the Swedish physical scientist Arrhenius proposed a low
About a century ago, the Swedish physical scientist Arrhenius proposed a low
游客
2025-01-03
22
管理
问题
About a century ago, the Swedish physical scientist Arrhenius proposed a low of classical chemistry that relates chemical reaction rate to temperature. According to his equation, chemical reactions are increasingly unlikely to occur as temperature approaches absolute zero, and at absolute zero, reactions stop. However, recent experiment evidence reveals that although the Arrhenius equation is generally accurate in describing the kind of chemical reaction that occurs at relatively high temperature, at temperatures closer to zero a quantum-mechanical effect known as tunneling comes into play; this effect accounts for chemical reactions that are forbidden by the principles of classical chemistry. Specifically, entire molecules can tunnel through the barriers of repulsive forces from other molecules and chemically react even though these molecules do not have sufficient energy, according to classical chemistry, to overcome the repulsive barrier.
The rate of any chemical reaction, regardless of the temperature at which it takes place, usually depends on a very important characteristic known as its activation energy. Any molecule can be imagined to reside at the bottom of a so-called potential well of energy. Some chemical reaction corresponds to the transition of a molecule from the bottom of one potential well to the bottom of another. In classical chemistry, such a transition can be accomplished only by going over the potential barrier between the well, the height of which remain constant and is called the activation energy of the reaction. In tunneling, the reacting molecules tunnel from the bottom of one to the bottom of another well without having to rise over the harrier between the two wells. Recently researchers have developed the concept of tunneling temperature: the temperature below which tunneling transitions greatly outnumber Arrhenius transitions, and classical mechanics gives way to its quantum counterpart.
This tunneling phenomenon at very low temperatures suggested my hypothesis about a cold prehistory of life: formation of rather complex organic molecules in the deep cold of outer space, where temperatures usually reach only a few degrees Kelvin. Cosmic rays might trigger the synthesis of simple molecules, such as interstellar formaldehyde, in dark clouds of interstellar dust. Afterward complex organic molecules would be formed, slowly hut surely, by means of tunneling. After I offered my hypothesis, Hoyle and Wickramashinghe argued that molecules of interstellar formaldehyde have indeed evolved into stable polysaccharides such as cellulose and starch. Their conclusions, although strongly disputed, have generated excitement among investigators such as myself who are proposing that the galactic clouds are the places where the prebiological evolution of compounds necessary to life occurred. [br] The author’s attitude toward the theory of a cold prehistory of life can best be described as ______.
选项
A、neutral
B、skeptical
C、mildly positive
D、very supportive
答案
C
解析
有点肯定。因为证实了作者之假设。
转载请注明原文地址:https://tihaiku.com/zcyy/3896889.html
相关试题推荐
Acenturyago,acutorevenadecayedtoothwerecausesforalarm,astheyc
Acenturyago,acutorevenadecayedtoothwerecausesforalarm,astheyc
JonasFrisenhadhiseurekamomentin1997.Backthen,scientistssuspectedt
JonasFrisenhadhiseurekamomentin1997.Backthen,scientistssuspectedt
JonasFrisenhadhiseurekamomentin1997.Backthen,scientistssuspectedt
In17th-centuryNewEngland,almosteveryonebelievedinwitches.Struggling
In17th-centuryNewEngland,almosteveryonebelievedinwitches.Struggling
In17th-centuryNewEngland,almosteveryonebelievedinwitches.Struggling
______isproposedbyM.A.K.Halliday.A、Systemic-functionalgrammarB、Universal
Thedistinctionbetweencompetenceandperformanceisproposedby______.A、Sauss
随机试题
HowtoPlanYourFutureCareerForafewmonthsbef
AllthepeopleworkingforSamWaltonadmire______.(他管理沃尔玛公司的方法和他对待员工的方式).thew
简答题:根据所给材料回答问题。(本题20分) 2015年,著名插画家刘某接受甲
编辑加工题:阅读分析短稿,并按照稿件加工整理的规范进行编辑加工。(本题20分)
涉及( )个以上行政区域的,由有关行政区域共同的上级执法部门负责,或者由各有关
A.ACTH水平下降 B.血管升压素分泌增加 C.儿茶酚胺水平增加 D.生
自动喷水灭火系统是一种最广泛的灭火系统,其优点有()。A.适应范围广
对某商场地下车库的机械排烟系统进行验收时,选择一个防烟分区的一只感温探测器和一只
三叉神经痛的诊断性封闭以下错误的是A.圆孔 B.卵圆孔 C.上颌结节 D.
(2020年真题)项目监理机构建立工程项目质量控制系统的工作内容有( )。A.确
最新回复
(
0
)