activation energy

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ac·ti·va·tion energy

The least amount of energy needed for a chemical reaction to occur. For example, striking a match on the side of a matchbox provides the activation energy, in the form of heat, necessary for the chemicals in the match to catch fire.
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Noun1.activation energy - the energy that an atomic system must acquire before a process (such as an emission or reaction) can occur; "catalysts are said to reduce the energy of activation during the transition phase of a reaction"
energy, free energy - (physics) a thermodynamic quantity equivalent to the capacity of a physical system to do work; the units of energy are joules or ergs; "energy can take a wide variety of forms"
aktivacijska energija
References in periodicals archive ?
The activation energy Q usually equals to activation enthalpy [DELTA]H.
Kinetic evidence of an apparent negative activation enthalpy in an organocatalytic process.
Figure 4 displays the activation enthalpy of the motional modes in Fig.
Thermal inactivation of enzyme was characterized by the activation enthalpy (HD 866a kJ/mol) which was much lower than that of the wild culture (Table II).
Seven research papers are also included, reporting on such matters as the effect of natural aging on some plastically deformed aluminum alloys using two different techniques, determining the activation energy for the formation and migration of thermal vacancies in 2024 aircraft material using different techniques and methods, and an annealing study of aluminum-magnesium wrought alloys using two different techniques and estimating the activation enthalpy of migrating defects.
The calculated values of the apparent activation energy Ea, activation enthalpy AHa, and activation entropy AS,, are given in Table 3.
Figure 4 presents the OIT activation enthalpy plot of two of the films.
The energy of activated molecules is a kind of triplet consisting mostly of three components: activation enthalpy, activation entropy and free energy of activation [8, 22].