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
2024-04-22
18
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 me 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. A 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 remains constant and is called the activation energy of the reaction. In tunneling, the reactings molecules tunnel from the bottom of one to the bottom of another well without having to rise over the barrier 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 but 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] Which of the following best describes the hypothesis of Hoyle and Wickramas-inghe?
选项
A、Molecules of interstellar formaldehyde can evolve into complex organic molecules.
B、Interstellar formaldehyde can be synthesized by tunneling.
C、Cosmic rays can directly synthesize complex organic molecules.
D、The galactic clouds are the places where prebiological evolution of compounds necessary to life occurred.
答案
A
解析
细节题。根据“Hoyle and Wickramasinghe”定位至文章第三段After I offeredmy hypothesis,Hoyle and Wickramashinghe argued that molecules of interstellarformaldehyde have indeed evolved into stable polysaccharides such as cellulose and starch.“当我提出了我的假设后,Hoyle和Wickramashinghe两位化学家指出星际甲醛分子确实进化为类似纤维素和淀粉等多糖酶。”这和选项A的表述一致,所以答案是A。
转载请注明原文地址:https://tihaiku.com/zcyy/3566750.html
相关试题推荐
Aboutacenturyago,theSwedishphysicalscientistArrheniusproposedalow
Aboutacenturyago,theSwedishphysicalscientistArrheniusproposedalow
Aboutacenturyago,theSwedishphysicalscientistArrheniusproposedalow
Before1965manyscientistspicturedthecirculationoftheocean’swaterma
Before1965manyscientistspicturedthecirculationoftheocean’swaterma
Before1965manyscientistspicturedthecirculationoftheocean’swaterma
Before1965manyscientistspicturedthecirculationoftheocean’swaterma
Aboutacenturyago,theSwedishphysicalscientistArrheniusproposedalow
Aboutacenturyago,theSwedishphysicalscientistArrheniusproposedalow
Before1965manyscientistspicturedthecirculationoftheocean’swaterma
随机试题
下列属于上大学的间接成本的是()。A.政府为学生提供无息或低息的学生贷款
男性,55岁,身高175cm,体重60kg,有慢性肝炎史15年,主诉肝区胀痛1个
不变资本和可变资本数量构成上的比例是资本的A.有机构成? B.价值构成 C
门窗框、扇的安装必须牢固,其固定片和膨胀螺栓的数量与位置应按框外围间距不大于60
有关立体视觉的叙述,错误的是A.立体视觉又称空间视觉 B.它表示两个物体相对的
A.隔夜地塞米松抑制试验 B.ACTH兴奋试验 C.酚妥拉明试验 D.禁水
穿心莲的功效是A、清热解毒,敛疮 B、清热凉血,祛瘀止痛 C、清热解毒,明目
围护结构隔热的方法有()。A、外表面采用浅色处理 B、设墙面遮阳 C、设置通
β-地中海贫血与下列何项无关A.临床表现为贫血、脾大、黄疸B.肽链数量不平衡C.
影响建筑产品法定使用寿命的因素有()。A.建筑产品的技术寿命 B.建筑
最新回复
(
0
)