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  2. Acid dissociation constant - Wikipedia

    en.wikipedia.org/wiki/Acid_dissociation_constant

    Free energy is made up of an enthalpy term and an entropy term. [11] = The standard enthalpy change can be determined by calorimetry or by using the van 't Hoff equation, though the calorimetric method is preferable. When both the standard enthalpy change and acid dissociation constant have been determined, the standard entropy change is easily ...

  3. PKA (irradiation) - Wikipedia

    en.wikipedia.org/wiki/PKA_(irradiation)

    Atoms can only be displaced if, upon bombardment, the energy they receive exceeds a threshold energy E d. Likewise, when a moving atom collides with a stationary atom, both atoms will have energy greater than E d after the collision only if the original moving atom had an energy exceeding 2 E d .

  4. Van 't Hoff equation - Wikipedia

    en.wikipedia.org/wiki/Van_'t_Hoff_equation

    For a reversible reaction, the equilibrium constant can be measured at a variety of temperatures. This data can be plotted on a graph with ln K eq on the y-axis and ⁠ 1 / T ⁠ on the x axis. The data should have a linear relationship, the equation for which can be found by fitting the data using the linear form of the Van 't Hoff equation

  5. Field effect (chemistry) - Wikipedia

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

    The concentration of negative charge on each chlorine has a through space effect which can be seen in the relative pKa values. [16] When the chlorines are pointed over the carboxylic acid group, the pKa is higher because loss of a proton is less favorable due to the increase in negative charge in the area.

  6. Negative energy - Wikipedia

    en.wikipedia.org/wiki/Negative_energy

    The negative-energy particle then crosses the event horizon into the black hole, with the law of conservation of energy requiring that an equal amount of positive energy should escape. In the Penrose process , a body divides in two, with one half gaining negative energy and falling in, while the other half gains an equal amount of positive ...

  7. Dissociation constant - Wikipedia

    en.wikipedia.org/wiki/Dissociation_constant

    In chemistry, biochemistry, and pharmacology, a dissociation constant (K D) is a specific type of equilibrium constant that measures the propensity of a larger object to separate (dissociate) reversibly into smaller components, as when a complex falls apart into its component molecules, or when a salt splits up into its component ions.

  8. Acid strength - Wikipedia

    en.wikipedia.org/wiki/Acid_strength

    Acid strength is the tendency of an acid, symbolised by the chemical formula, to dissociate into a proton, +, and an anion, .The dissociation or ionization of a strong acid in solution is effectively complete, except in its most concentrated solutions.

  9. Proton affinity - Wikipedia

    en.wikipedia.org/wiki/Proton_affinity

    The higher the proton affinity, the stronger the base and the weaker the conjugate acid in the gas phase.The (reportedly) strongest known base is the ortho-diethynylbenzene dianion (E pa = 1843 kJ/mol), [3] followed by the methanide anion (E pa = 1743 kJ/mol) and the hydride ion (E pa = 1675 kJ/mol), [4] making methane the weakest proton acid [5] in the gas phase, followed by dihydrogen.