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  2. List of physical constants - Wikipedia

    en.wikipedia.org/wiki/List_of_physical_constants

    The constants listed here are known values of physical constants expressed in SI units; that is, physical quantities that are generally believed to be universal in nature and thus are independent of the unit system in which they are measured. Many of these are redundant, in the sense that they obey a known relationship with other physical ...

  3. Benzoic acid - Wikipedia

    en.wikipedia.org/wiki/Benzoic_acid

    Benzoic acid is cheap and readily available, so the laboratory synthesis of benzoic acid is mainly practiced for its pedagogical value. It is a common undergraduate preparation. Benzoic acid can be purified by recrystallization from water because of its high solubility in hot water and poor solubility in cold water. The avoidance of organic ...

  4. Hammett equation - Wikipedia

    en.wikipedia.org/wiki/Hammett_equation

    The starting point for the collection of the substituent constants is a chemical equilibrium for which the substituent constant is arbitrarily set to 0 and the reaction constant is set to 1: the deprotonation of benzoic acid or benzene carboxylic acid (R and R' both H) in water at 25 °C. Scheme 1. Dissociation of benzoic acids

  5. Category:Physical constants - Wikipedia

    en.wikipedia.org/wiki/Category:Physical_constants

    Pages in category "Physical constants" The following 37 pages are in this category, out of 37 total. This list may not reflect recent changes. ...

  6. Taft equation - Wikipedia

    en.wikipedia.org/wiki/Taft_equation

    where log(k s /k CH 3) B is the ratio of the rate of the base catalyzed reaction compared to the reference reaction, log(k s /k CH 3) A is ratio of a rate of the acid catalyzed reaction compared to the reference reaction, and ρ* is a reaction constant that describes the sensitivity of the reaction series. For the definition reaction series, ρ ...

  7. Inductive effect - Wikipedia

    en.wikipedia.org/wiki/Inductive_effect

    The strength of a carboxylic acid depends on the extent of its ionization constant: the more ionized it is, the stronger it is. As an acid becomes stronger, the numerical value of its pK a drops. In acids, the electron-releasing inductive effect of the alkyl group increases the electron density on oxygen and thus hinders the breaking of the O-H ...

  8. List of common physics notations - Wikipedia

    en.wikipedia.org/wiki/List_of_common_physics...

    Faraday constant: coulombs per mole (C⋅mol −1) frequency: hertz (Hz) function: friction: newton (N) electrical conductance: siemens (S) universal gravitational constant: newton meter squared per kilogram squared (N⋅m 2 /kg 2) shear modulus: pascal (Pa) or newton per square meter (N/m 2) gluon field strength tensor

  9. Ortho effect - Wikipedia

    en.wikipedia.org/wiki/Ortho_effect

    Ortho effect is an organic chemistry phenomenon where the presence of a chemical group at the at ortho position or the 1 and 2 position of a phenyl ring, relative to the carboxylic compound changes the chemical properties of the compound.