When considering molecular conformations, which of the following statements are true?

Question

BlackTom AI · Accepted Answer

Begin by examining what determines conformational changes in molecules. 
Option 1: 'Different conformations are generally reached by rotation about a C-C single bond, a low energy process.' This is correct because rotation around a C-C single bond typically has a small energy barrier (torsional barrier), allowing interconversion between conformations at moderate temperatures without breaking bonds. This is the classic mechanism for conformational changes in alkanes and many other molecules. 
Option 2: 'At room temperature conformations of ethane do not interchange.' This is incorrect; ethane readily undergoes torsional rotation about its C-C bond, leading to rapid interconversion of staggered and eclipsed conformations even at room temperature. 
Option 3: 'Different conformations are generally reached by rotation about a C-C single bond, a high energy process.' While rotation about a C-C single bond is indeed a rotation process, calling it high energy is inaccurate for many simple systems like ethane; the energy barrier is relatively low. The statement mischaracterizes the typical energy landscape of single-bond rotations. 
Option 4: 'Different conformations are generally reached by breaking and reforming C-C bonds.' This is wrong because conformational changes occur through bond rotations without breaking the bonds; breaking and reforming C-C bonds would constitute chemical reactions altering connectivity, not mere conformational interconversion. 
In summary, the only statement aligning with established understanding of conformational dynamics is Option 1, as it correctly identifies rotation about C-C single bonds as the low-energy mechanism driving interconversion between conformers.

When considering molecular conformations, which of the following statements are true?单项选择题

类似问题

Consider the following Newman projections (i – iii) of an alkylhalide showing all the staggered conformations about the C2-C1 bond. Key: X = a bulky halide group.Which of the following lists the conformers, i – iii, from lowest to highest energy?

Consider the Newman projections (i - vi) looking down the C2 - C3 bond in n-butane. Select the LOWEST energy conformer of n-butane?

Consider the Newman projections (i - vi) looking down the C2 - C3 bond in n-butane. Select the highest energy conformer of n-butane?

What is the primary use of distance and angle measurements in molecular dynamics (MD) simulations?

What was the world's first widely adopted biodiversity policy?

The aim of the Paris Agreement is to ensure that the earth’s preindustrial temperature is not exceeded by more than º Celsius.

更多留学生实用工具

智能学习助手

风格化写作助手

论文查重助手

文献引用助手

课堂转译助手

课堂笔记助手

Quiz搜索助手

学校历年真题

智能刷题助手

智能匹配练习

希望你的学习变得更简单