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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)

    In its path, a PKA can produce effects similar to those of heating and rapidly quenching a metal, resulting in Frenkel defects. A thermal spike does not last long enough to permit annealing of the Frenkel defects. [1] [2] A different model called the displacement spike was proposed for fast neutron bombardment of heavy elements.

  4. 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 ...

  5. List of common physics notations - Wikipedia

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

    time: second (s) four-velocity: meter per second (m/s) potential energy: joule (J) internal energy: joule (J) relativistic mass: kilogram (kg) energy density: joule per cubic meter (J/m 3) specific energy: joule per kilogram (J/kg) voltage also called electric potential difference volt (V)

  6. Zeta potential - Wikipedia

    en.wikipedia.org/wiki/Zeta_potential

    Zeta potential can also be used for the pKa estimation of complex polymers that is otherwise difficult to measure accurately using conventional methods. This can help studying the ionisation behaviour of various synthetic and natural polymers under various conditions and can help in establishing standardised dissolution-pH thresholds for pH ...

  7. 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.

  8. Time in physics - Wikipedia

    en.wikipedia.org/wiki/Time_in_physics

    Foucault's pendulum in the Panthéon of Paris can measure time as well as demonstrate the rotation of Earth. In physics , time is defined by its measurement : time is what a clock reads. [ 1 ] In classical, non-relativistic physics, it is a scalar quantity (often denoted by the symbol t {\displaystyle t} ) and, like length , mass , and charge ...

  9. Protein pKa calculations - Wikipedia

    en.wikipedia.org/wiki/Protein_pKa_calculations

    In computational biology, protein pK a calculations are used to estimate the pK a values of amino acids as they exist within proteins.These calculations complement the pK a values reported for amino acids in their free state, and are used frequently within the fields of molecular modeling, structural bioinformatics, and computational biology.