Jove
Visualize
联系我们
JoVE
x logofacebook logolinkedin logoyoutube logo
关于 JoVE
概览领导团队博客JoVE 帮助中心
作者
出版流程编辑委员会范围与政策同行评审常见问题投稿
图书馆员
用户评价订阅访问资源图书馆顾问委员会常见问题
研究
JoVE JournalMethods CollectionsJoVE Encyclopedia of Experiments存档
教育
JoVE CoreJoVE BusinessJoVE Science EducationJoVE Lab Manual教师资源中心教师网站
使用条款与条件
隐私政策
政策

相关概念视频

Phase Transitions: Vaporization and Condensation02:39

Phase Transitions: Vaporization and Condensation

The physical form of a substance changes on changing its temperature. For example, raising the temperature of a liquid causes the liquid to vaporize (convert into vapor). The process is called vaporization—a surface phenomenon. Vaporization occurs when the thermal motion of the molecules overcome the intermolecular forces, and the molecules (at the surface) escape into the gaseous state. When a liquid vaporizes in a closed container, gas molecules cannot escape. As these gas phase molecules...
Clausius-Clapeyron Equation02:35

Clausius-Clapeyron Equation

The equilibrium between a liquid and its vapor depends on the temperature of the system; a rise in temperature causes a corresponding rise in the vapor pressure of its liquid. The Clausius-Clapeyron equation gives the quantitative relation between a substance’s vapor pressure (P) and its temperature (T); it predicts the rate at which vapor pressure increases per unit increase in temperature.
Physical Properties Affecting Solubility02:19

Physical Properties Affecting Solubility

Solutions of Gases in Liquids
As for any solution, the solubility of a gas in a liquid is affected by the attractive intermolecular forces between solute and solvent species. Unlike solid and liquid solutes, however, there is no solute-solute intermolecular attraction to overcome when a gaseous solute dissolves in a liquid solvent since the atoms or molecules comprising a gas are far separated and experience negligible interactions. Consequently, solute-solvent interactions are the sole...
Vapor Pressure Lowering03:28

Vapor Pressure Lowering

The equilibrium vapor pressure of a liquid is the pressure exerted by its gaseous phase when vaporization and condensation are occurring at equal rates: Dissolving a nonvolatile substance in volatile liquid results in a lowering of the liquid’s vapor pressure. This phenomenon can be explained by considering the effect of added solute molecules on the liquid's vaporization and condensation processes. To vaporize, solvent molecules must be present at the surface of the solution. The presence of...
Physical Properties of Ethers02:17

Physical Properties of Ethers

Overview
An ether molecule has a net dipole moment due to the polarity of C–O bonds. Subsequently, boiling points of ethers are lower than those of alcohols of comparable molecular weight and slightly higher than those of hydrocarbons of comparable molecular weight (Table 1).
Ethers can act as hydrogen bond acceptors, making them more water-soluble than hydrocarbons, but since ethers cannot act as hydrogen bond donors, they are much less soluble in water than alcohols. Ethers are considered...
Volatilization01:10

Volatilization

Volatilization gravimetry is an analytical technique that measures the mass lost due to the volatilization of the substance. This technique is used to estimate the amount of volatile material in a sample. To perform this method, heat a known amount of the sample to a high temperature in a crucible or other suitable vessel. The volatile substance in the sample evaporates, and the vapor is completely expelled from the crucible either by heating the sample or bubbling a stream of inert gas through...

您也可能阅读

相关文章

通过共同作者、期刊和引用图与本文相关的文章。

排序
Same author

Correction: The mineralocorticoid receptor antagonist finerenone enhances cardiovascular recovery upon food intake normalization in obese mice.

Cardiovascular diabetology·2026
Same author

Benefit of combination therapy with dapagliflozin and eplerenone on cardiac function and fibrosis in rats with non-diabetic chronic kidney disease.

Scientific reports·2024
Same author

On 'Is vitamin E the only lipid-soluble, chain-breaking antioxidant in human blood plasma and erythrocyte membranes?' by Graham W. Burton, Anne Joyce, Keith U. Ingold.

Archives of biochemistry and biophysics·2022
Same author

Value of magnetic resonance imaging for evaluating muscle inflammation: insights from a new mouse model of myositis.

Neuropathology and applied neurobiology·2017
Same author

Variable cartilage degradation in mice with diet-induced metabolic dysfunction: food for thought.

Osteoarthritis and cartilage·2017
Same author

Absolute Rate Constants for Radical Additions to Alkenes in Solution. The Synergistic Effect of Perfluorination on the Reactivities of n-Alkyl Radicals<sup>1</sup>.

The Journal of organic chemistry·2017

相关实验视频

Updated: Jun 18, 2026

Fizzy Extraction of Volatile Organic Compounds Combined with Atmospheric Pressure Chemical Ionization Quadrupole Mass Spectrometry
08:10

Fizzy Extraction of Volatile Organic Compounds Combined with Atmospheric Pressure Chemical Ionization Quadrupole Mass Spectrometry

Published on: July 14, 2017

基乙醇和醇的氧-碳键解离热量. 温度依赖的替代效应的一个例子.

D A Pratt1, M I de Heer, P Mulder

  • 1Steacie Institute for Molecular Sciences, National Research Council of Canada, 100 Sussex Drive, Ottawa, Canada K1A 0R6.

Journal of the American Chemical Society
|June 8, 2001
PubMed
概括

替代效应对债券解离度 (BDE) 取决于基稳定,而不仅仅是债券极性. 高温可以改变替代剂的方向,与298K值相比,显著影响测量的BDE.

科学领域:

  • 物理有机化学 有机化学
  • 计算化学计算化学
  • 化学热力学化学热力学

背景情况:

  • 传统上,对债券解离度 (BDE) 的替代效应与债券极性有关.
  • 之前对化的DFT计算显示,替代剂对BDE的影响很小.
  • 一个新的假设提出了激进稳定/不稳定是显著替代物效应的主要驱动因素.

研究的目的:

  • 调查替代剂稳定/不稳定对Z-X键解离度 (BDE) 的作用.
  • 通过理论和实验方法研究Y替代剂对4-YC(6) H(4) O-X BDEs的影响.
  • 使用哈梅特型图表量化替代物效应,并比较不同温度的结果.

主要方法:

  • 用密度函数理论 (DFT) 的计算来确定BDE.
  • 对各种Y替代的非单离子衍生物进行了BDE的实验测量.
  • 哈梅特型图 (DeltaBDE与sigma(+)) 用于分析替代效应.

主要成果:

  • DFT的计算和实验显示了对O-X BDEs的显著和一致的替代效应 (rho(+) = 6.7-6.9 kcal mol(-1)).
  • 在高温 (大约. 1000 K) 对O-CH的实验BDE显示,与环境温度相比,替代效应减少.

更多相关视频

Separation of Aldehydes and Reactive Ketones from Mixtures Using a Bisulfite Extraction Protocol
09:08

Separation of Aldehydes and Reactive Ketones from Mixtures Using a Bisulfite Extraction Protocol

Published on: April 2, 2018

Versatile CO2 Transformations into Complex Products: A One-pot Two-step Strategy
07:36

Versatile CO2 Transformations into Complex Products: A One-pot Two-step Strategy

Published on: November 9, 2019

相关实验视频

Last Updated: Jun 18, 2026

Fizzy Extraction of Volatile Organic Compounds Combined with Atmospheric Pressure Chemical Ionization Quadrupole Mass Spectrometry
08:10

Fizzy Extraction of Volatile Organic Compounds Combined with Atmospheric Pressure Chemical Ionization Quadrupole Mass Spectrometry

Published on: July 14, 2017

Separation of Aldehydes and Reactive Ketones from Mixtures Using a Bisulfite Extraction Protocol
09:08

Separation of Aldehydes and Reactive Ketones from Mixtures Using a Bisulfite Extraction Protocol

Published on: April 2, 2018

Versatile CO2 Transformations into Complex Products: A One-pot Two-step Strategy
07:36

Versatile CO2 Transformations into Complex Products: A One-pot Two-step Strategy

Published on: November 9, 2019

  • 这种在高温下降低的原因是由于自由旋转而导致结合替代物的平面性丧失 (例如,-OCH(3)).
  • 结论:

    • 对BDE的替代效应主要由激进稳定/不稳定决定,而不仅仅是由键极性决定.
    • 高温可以显著改变替代剂的方向,从而修改观察到的BDE.
    • 高温测量在标准条件下 (298 K) 可能无法准确反映替代物效应.