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R is the gas constant and T is the absolute temperature. Note that pK a = −log(K a) and 2.303 ≈ ln(10). At 25 °C, ΔG ⊖ in kJ·mol −1 ≈ 5.708 pK a (1 kJ·mol −1 = 1000 joules per mole). Free energy is made up of an enthalpy term and an entropy term. [11] =
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The constants listed here are known values of physical constants expressed in SI units; that is, physical quantities that are generally believed to be universal in nature and thus are independent of the unit system in which they are measured.
Boiling liquid oxygen This is a list of gases at standard conditions , which means substances that boil or sublime at or below 25 °C (77 °F) and 1 atm pressure and are reasonably stable. List
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.
The molar gas constant (also known as the gas constant, universal gas constant, or ideal gas constant) is denoted by the symbol R or R. It is the molar equivalent to the Boltzmann constant , expressed in units of energy per temperature increment per amount of substance , rather than energy per temperature increment per particle .
For gases, departure from 3 R per mole of atoms is generally due to two factors: (1) failure of the higher quantum-energy-spaced vibration modes in gas molecules to be excited at room temperature, and (2) loss of potential energy degree of freedom for small gas molecules, simply because most of their atoms are not bonded maximally in space to ...
The solvent (e.g. water) is omitted from this expression when its concentration is effectively unchanged by the process of acid dissociation. The strength of a weak acid can be quantified in terms of a dissociation constant , K a {\displaystyle K_{a}} , defined as follows, where [ X ] {\displaystyle {\ce {[X]}}} signifies the concentration of a ...