相关实验视频

Updated: Jun 30, 2025

Measuring Dissolved Methane in Aquatic Ecosystems Using An Optical Spectroscopy Gas Analyzer
05:00

Measuring Dissolved Methane in Aquatic Ecosystems Using An Optical Spectroscopy Gas Analyzer

Published on: July 26, 2024

435

为长寿命气体推导全球OH丰度和大气寿命:寻找CH3的替代品

Qing Liang1,2, Martyn P Chipperfield3, Eric L Fleming1,4

  • 1Atmospheric Chemistry and Dynamics Laboratory, NASA Goddard Space Flight Center, Greenbelt, Maryland, USA.

Journal of geophysical research. Atmospheres : JGR
|March 22, 2024
PubMed
概括

随着甲基化 (MCF) 的下降,HFC和HCFC的组合提供了一种测量全球基 (OH) 丰度的新方法. 这种多种方法有助于预测空气质量和气候影响.

更多相关视频

Assessment of Methane and Nitrous Oxide Fluxes from Paddy Field by Means of Static Closed Chambers Maintaining Plants Within Headspace09:03

Assessment of Methane and Nitrous Oxide Fluxes from Paddy Field by Means of Static Closed Chambers Maintaining Plants Within Headspace

Published on: September 6, 2018

12.3K
Design and Use of a Full Flow Sampling System FFS for the Quantification of Methane Emissions08:18

Design and Use of a Full Flow Sampling System FFS for the Quantification of Methane Emissions

Published on: June 12, 2016

16.7K

相关概念视频

Noble Gases02:54

Noble Gases


The elements in group 18 are noble gases (helium, neon, argon, krypton, xenon, and radon). They earned the name “noble” because they were assumed to be nonreactive since they have filled valence shells. In 1962, Dr. Neil Bartlett at the University of British Columbia proved this assumption to be false.
17.5K
Radical Substitution: Halogenation of Alkanes and Alkyl Substituents01:27

Radical Substitution: Halogenation of Alkanes and Alkyl Substituents

In the presence of heat or light, alkanes react with molecular halogens to form alkyl halides by a substitution reaction called radical halogenation. This reaction has three steps: initiation, propagation, and termination, as seen in the radical chlorination of methane to produce methyl chloride.
In the initiation step of the reaction, the chlorine molecule undergoes homolytic cleavage in the presence of light or heat, forming two highly reactive chlorine radicals. Propagation occurs in two...
8.1K
The Equilibrium Constant03:11

The Equilibrium Constant

Consider the oxidation of sulfur dioxide:
47.7K
Halogens03:01

Halogens

Group 17 elements, known as halogens, are nonmetals. At room temperature, fluorine and chlorine are gases, bromine is a liquid, and iodine a solid. Astatine is a highly unstable radioactive element, so currently, most of its properties are unknown due to its short half-life. Tennessine is a synthetic element also predicted to be in this group. 
18.5K
Mass Spectrometry: Alkyl Halide Fragmentation01:22

Mass Spectrometry: Alkyl Halide Fragmentation

Chlorine isotopes exist as 35Cl and 37Cl in a 3:1 ratio, while bromine isotopes exist as 79Br and 81Br in a 1:1 ratio. The mass spectrum of alkyl halides typically produces two distinct molecular ion peaks, the molecular ion peak, [M], and the molecular ion plus two, [M + 2] peak. The relative heights of these two peaks are proportional to the isotopic abundance ratios of the halide. For example, 2‐chloropropane and 1‐bromopropane display two peaks with relative peak heights in a 3:1 and...
1.1K
Radical Halogenation: Thermodynamics01:34

Radical Halogenation: Thermodynamics

The thermodynamic favorability of a reaction is determined by the change in Gibbs free energy (ΔG). ΔG has two components- enthalpy (ΔH) and entropy (ΔS). The entropy component is negligible for alkane halogenation because the number of reactants and product molecules are equal. In this case, the ΔG is governed only by the enthalpy component. The most crucial factor that determines ΔH is the strength of the bonds. ΔH can be determined by comparing the energy...
3.8K