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单词 reactivity
释义

reactivity


re·ac·tive

R0067200 (rē-ăk′tĭv)adj.1. Tending to be responsive or to react to a stimulus.2. Characterized by reaction.3. Chemistry & Physics Tending to participate readily in reactions.
re·ac′tive·ly adv.re·ac′tive·ness, re′ac·tiv′i·ty n.
Thesaurus
Noun1.reactivity - responsive to stimulationresponsivenesssensitivity, sensitiveness, sensibility - (physiology) responsiveness to external stimuli; the faculty of sensation; "sensitivity to pain"excitability, irritability - excessive sensitivity of an organ or body part
2.reactivity - ready susceptibility to chemical changesusceptibility, susceptibleness - the state of being susceptible; easily affected
Translations
réactivitéreattività

Reactivity


reactivity

[‚rē·ak′tiv·əd·ē] (chemistry) The relative capacity of an atom, molecule, or radical to combine chemically with another atom, molecule, or radical. (nucleonics) A measure of the deviation of a nuclear reactor from the critical state at any instant of time such that positive and negative values correspond to reactors above and below critical, respectively; measured in percent k, millikays, dollars, or in-hours.

Reactivity

 

a measure of the chemical activity of substances accounting for the variety and rate of the reactions possible for a given substance. For example, noble metals (Au, Pt) and inert gases (He, Ar, Kr, Xe) are chemically inactive; that is, they possess low reactivity. Alkali metals (Li, Na, K, Cs) and halogens (F, Cl, Br, I), on the other hand, are chemically active; that is, they possess high reactivity.

In organic chemistry, alkanes are characterized by low reactivity and therefore can undergo only reactions (radical halo-genation and nitration, dehydrogenation, dissociation with rupture of C—C bond) occurring under such vigorous conditions as elevated temperatures and ultraviolet irradiation. For the alkyl halides, additional reactions, such as dehydrohalogen-ation, nucleophilic substitution for the halogen, and the formation of organomagnesium compounds, are possible under mild conditions. The presence of double or triple bonds or functional groups (hydroxyl —OH, carboxyl —COOH, amino —NH2) in a molecule promotes a further increase in reactivity.

Reactivity is quantitatively expressed by specific rate constants or, in the case of reversible processes, by equilibrium constants. Modern concepts of reactivity are based on the valence-bond theory and on the study of the distribution (and displacement upon action of a reagent) of the electron density in a molecule. Electron displacements are defined qualitatively through inductive and mesomeric effects and quantitatively through quantum-mechanical calculations. The key factor determining the relative reactivity of a number of related compounds is the molecular structure, which encompasses the nature of the substituents, the electronic and steric effect of these substituents on the reaction center, and the geometry of the molecule. Reactivity is dependent on the reaction conditions, for example, the nature of the medium, presence of catalysts or inhibitors, pressure, temperature, and irradiation. Depending on the mechanism of a given reaction, these factors all have a varied and sometimes contrary effect on the reaction rate. The quantitative relationship between rate (or equilibrium) constants within one reaction series may be represented by correlation equations, which describe the change in the constant as a function of the change in a given parameter. Examples are seen in the Hammett-Taft equation, which deals with the effect of a substituent, and the Brønsted equation, which deals with solvent polarity.

reactivity


reactivity

 [re″ak-tiv´ĭ-te] the process or property of reacting.

re·ac·tiv·i·ty

(rē-ak-tiv'i-tē), 1. The property of reacting, chemically, immunologically or in any other sense. 2. The process of reacting.

re·ac·tiv·i·ty

(rē'ak-tiv'i-tē) 1. The property of reacting, chemically or in any other sense. 2. The process of reacting.

Patient discussion about reactivity

Q. Does anyone have experience treating reactive arthritis? symtoms: bladder incontence, sore joint, eye irritation, cracked fingers and lips A. The management of reactive arthritis usually starts with pain killers and injection of steroids into the joints, and if necessary, stronger medications. Due to the severity of this condition, consulting a doctor may be wise.
You may read more here:
www.nlm.nih.gov/medlineplus/ency/article/000440.htm

More discussions about reactivity

reactivity


Related to reactivity: Reactivity series
  • noun

Synonyms for reactivity

noun responsive to stimulation

Synonyms

  • responsiveness

Related Words

  • sensitivity
  • sensitiveness
  • sensibility
  • excitability
  • irritability

noun ready susceptibility to chemical change

Related Words

  • susceptibility
  • susceptibleness
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更新时间:2025/3/20 0:53:08