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  2. Acid dissociation constant - Wikipedia

    en.wikipedia.org/wiki/Acid_dissociation_constant

    The first point to note is that, when pK a is positive, the standard free energy change for the dissociation reaction is also positive. Second, some reactions are exothermic and some are endothermic, but, when ΔH ⊖ is negative TΔS ⊖ is the dominant factor, which determines that ΔG ⊖ is positive.

  3. Common-ion effect - Wikipedia

    en.wikipedia.org/wiki/Common-ion_effect

    Thus the percent dissociation of the acetic acid will decrease, and the pH of the solution will increase. The ionization of an acid or a base is limited by the presence of its conjugate base or acid. NaCH 3 CO 2 (s) → Na + (aq) + CH 3 CO 2 − (aq) CH 3 CO 2 H(aq) ⇌ H + (aq) + CH 3 CO 2 − (aq)

  4. Molar ionization energies of the elements - Wikipedia

    en.wikipedia.org/wiki/Molar_ionization_energies...

    The first molar ionization energy applies to the neutral atoms. The second, third, etc., molar ionization energy applies to the further removal of an electron from a singly, doubly, etc., charged ion. For ionization energies measured in the unit eV, see Ionization energies of the elements (data page). All data from rutherfordium onwards is ...

  5. Brønsted–Lowry acid–base theory - Wikipedia

    en.wikipedia.org/wiki/Brønsted–Lowry_acid...

    H 2 O is a base because it accepts a proton from CH 3 COOH and becomes its conjugate acid, the hydronium ion, (H 3 O +). [9] The reverse of an acid–base reaction is also an acid–base reaction, between the conjugate acid of the base in the first reaction and the conjugate base of the acid.

  6. Dissociation (chemistry) - Wikipedia

    en.wikipedia.org/wiki/Dissociation_(chemistry)

    The reaction of an acid in water solvent is often described as a dissociation + + where HA is a proton acid such as acetic acid, CH 3 COOH. The double arrow means that this is an equilibrium process, with dissociation and recombination occurring at the same time.

  7. Base (chemistry) - Wikipedia

    en.wikipedia.org/wiki/Base_(chemistry)

    The equilibrium constant for this reaction at 25 °C is 1.8 x 10 −5, [12] such that the extent of reaction or degree of ionization is quite small. Lewis bases A Lewis base or electron-pair donor is a molecule with one or more high-energy lone pairs of electrons which can be shared with a low-energy vacant orbital in an acceptor molecule to ...

  8. Ionization energy - Wikipedia

    en.wikipedia.org/wiki/Ionization_energy

    The first ionization energy is quantitatively expressed as X(g) + energy X + (g) + e −. where X is any atom or molecule, X + is the resultant ion when the original atom was stripped of a single electron, and e − is the removed electron. [2] Ionization energy is positive for neutral atoms, meaning that the ionization is an endothermic process.

  9. Koopmans' theorem - Wikipedia

    en.wikipedia.org/wiki/Koopmans'_theorem

    From Koopmans’ theorem the energy of the 1b 1 HOMO corresponds to the ionization energy to form the H 2 O + ion in its ground state (1a 1) 2 (2a 1) 2 (1b 2) 2 (3a 1) 2 (1b 1) 1. The energy of the second-highest MO 3a 1 refers to the ion in the excited state (1a 1) 2 (2a 1) 2 (1b 2) 2 (3a 1) 1 (1b 1) 2, and so on. In this case the order of the ...