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  2. Bond energy - Wikipedia

    en.wikipedia.org/wiki/Bond_energy

    It is sometimes called the mean bond, bond enthalpy, average bond enthalpy, or bond strength. [ 1 ] [ 2 ] [ 3 ] IUPAC defines bond energy as the average value of the gas-phase bond-dissociation energy (usually at a temperature of 298.15 K) for all bonds of the same type within the same chemical species.

  3. Bond-dissociation energy - Wikipedia

    en.wikipedia.org/wiki/Bond-dissociation_energy

    The term bond-dissociation energy is similar to the related notion of bond-dissociation enthalpy (or bond enthalpy), which is sometimes used interchangeably.However, some authors make the distinction that the bond-dissociation energy (D 0) refers to the enthalpy change at 0 K, while the term bond-dissociation enthalpy is used for the enthalpy change at 298 K (unambiguously denoted DH° 298).

  4. Standard enthalpy of reaction - Wikipedia

    en.wikipedia.org/wiki/Standard_enthalpy_of_reaction

    If the enthalpies for each step can be measured, then their sum gives the enthalpy of the overall single reaction. [11] Finally the reaction enthalpy may be estimated using bond energies for the bonds which are broken and formed in the reaction of interest. This method is only approximate, however, because a reported bond energy is only an ...

  5. Standard enthalpy of formation - Wikipedia

    en.wikipedia.org/wiki/Standard_enthalpy_of_formation

    Since the pressure of the standard formation reaction is fixed at 1 bar, the standard formation enthalpy or reaction heat is a function of temperature. For tabulation purposes, standard formation enthalpies are all given at a single temperature: 298 K, represented by the symbol Δ f H ⦵ 298 K.

  6. Carbon dioxide (data page) - Wikipedia

    en.wikipedia.org/wiki/Carbon_dioxide_(data_page)

    Structure and properties Index of refraction, n D: 1.000449 at 589.3 nm and 0 °C [1]: Dielectric constant, ε r: 1.60 ε 0 at 0 °C, 50 atm : Average energy per C=O bond : 804.4 kJ/mol at 298 K (25 °C) [2]

  7. Benson group increment theory - Wikipedia

    en.wikipedia.org/wiki/Benson_group_increment_theory

    This is a thermodynamic argument, and kinetics are ignored. As determined by the enthalpies below the corresponding molecules, the enthalpy of reaction for 2-methyl-1-butene going to 2-methyl-butane is −29.07 kcal/mol, which is in great agreement with the value calculated from NIST, [15] −28.31 kcal/mol. For 2-butanone going to 2-butanol ...

  8. Hess's law - Wikipedia

    en.wikipedia.org/wiki/Hess's_law

    Hess's law is useful in the determination of enthalpies of the following: [2] Heats of formation of unstable intermediates like CO (g) and NO (g). Heat changes in phase transitions and allotropic transitions. Lattice energies of ionic substances by constructing Born–Haber cycles if the electron affinity to form the anion is known, or

  9. Thiol - Wikipedia

    en.wikipedia.org/wiki/Thiol

    The S−H bond in thiols is weak compared to the O−H bond in alcohols. For CH 3 X−H, the bond enthalpies are 365.07 ± 2.1 kcal/mol for X = S and 440.2 ± 3.0 kcal/mol for X = O. [21] Hydrogen-atom abstraction from a thiol gives a thiyl radical with the formula RS •, where R = alkyl or aryl.