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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 ...
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 ...
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.
In this case, one can use various free energy calculation methods to obtain the protonation free energy [15] such as biased Metropolis MC, [24] free-energy perturbation, [25] [26] thermodynamic integration, [27] [28] [29] the non-equilibrium work method [30] or the Bennett acceptance ratio method. [31] Note that the pK HH
The relative activity of a species i, denoted a i, is defined [4] [5] as: = where μ i is the (molar) chemical potential of the species i under the conditions of interest, μ o i is the (molar) chemical potential of that species under some defined set of standard conditions, R is the gas constant, T is the thermodynamic temperature and e is the exponential constant.
The absolute temperature (Kelvin) scale can be loosely interpreted as the average kinetic energy of the system's particles. The existence of negative temperature, let alone negative temperature representing "hotter" systems than positive temperature, would seem paradoxical in this interpretation.
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.
The value of the equilibrium constant for the formation of a 1:1 complex, such as a host-guest species, may be calculated with a dedicated spreadsheet application, Bindfit: [4] In this case step 2 can be performed with a non-iterative procedure and the pre-programmed routine Solver can be used for step 3.