Search results
Results from the WOW.Com Content Network
Gas phase ion chemistry is a field of science encompassed within both chemistry and physics. It is the science that studies ions and molecules in the gas phase, most often enabled by some form of mass spectrometry. By far the most important applications for this science is in studying the thermodynamics and kinetics of reactions.
Chemical kinetics, also known as reaction kinetics, is the branch of physical chemistry that is concerned with understanding the rates of chemical reactions. It is different from chemical thermodynamics , which deals with the direction in which a reaction occurs but in itself tells nothing about its rate.
An example of such a reaction is the ring closure of cyclopentane biradicals generated from the gas-phase thermal decomposition of 2,3-diazabicyclo[2.2.1]hept-2-ene. [ 20 ] [ 21 ] Transition state theory is also based on the assumption that atomic nuclei behave according to classical mechanics . [ 22 ]
The rate for a bimolecular gas-phase reaction, A + B → product, predicted by collision theory is [6] = = ()where: k is the rate constant in units of (number of molecules) −1 ⋅s −1 ⋅m 3.
Usually, this mechanism is used in gas phase decomposition and also in isomerization reactions. An example of isomerization by a Lindemann mechanism is the isomerization of cyclopropane. [11] cyclo−C 3 H 6 → CH 3 −CH=CH 2. Although it seems like a simple reaction, it is actually a multistep reaction: cyclo−C 3 H 6 → CH 2 −CH 2 −CH ...
Understanding this is perhaps a "thought experiment" in chemical kinetics, but actual examples exist. A gas-phase reaction at constant temperature and pressure which results in an increase in the number of molecules will lead to an increase in volume. Inside a cylinder closed with a piston, it can proceed only by doing work on the piston.
This is a gas-phase reaction of phosphorus vapor, above the solid, with oxygen producing excited states of (PO) 2 and HPO. [7] Another gas phase reaction is the basis of nitric oxide detection in commercial analytic instruments applied to environmental air-quality testing.
Chemical inertness: The covalent link should be strong and inert to biological reactions. Kinetics: The reaction must be rapid so that covalent ligation is achieved prior to probe metabolism and clearance. The reaction must be fast, on the time scale of cellular processes (minutes) to prevent competition in reactions which may diminish the ...