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The gas constant occurs in the ideal gas law: = = where P is the absolute pressure, V is the volume of gas, n is the amount of substance, m is the mass, and T is the thermodynamic temperature. R specific is the mass-specific gas constant. The gas constant is expressed in the same unit as molar heat.
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.
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] =
The ionic strength of a solution is a measure of the concentration of ions in that solution. Ionic compounds, when dissolved in water, dissociate into ions. The total electrolyte concentration in solution will affect important properties such as the dissociation constant or the solubility of different salts. One of the main characteristics of a ...
In thermodynamics, an activity coefficient is a factor used to account for deviation of a mixture of chemical substances from ideal behaviour. [1] In an ideal mixture, the microscopic interactions between each pair of chemical species are the same (or macroscopically equivalent, the enthalpy change of solution and volume variation in mixing is zero) and, as a result, properties of the mixtures ...
The Van 't Hoff equation relates the change in the equilibrium constant, K eq, of a chemical reaction to the change in temperature, T, given the standard enthalpy change, Δ r H ⊖, for the process. The subscript r {\displaystyle r} means "reaction" and the superscript ⊖ {\displaystyle \ominus } means "standard".
The degree of dissociation in gases is denoted by the symbol α, where α refers to the percentage of gas molecules which dissociate. Various relationships between K p and α exist depending on the stoichiometry of the equation. The example of dinitrogen tetroxide (N 2 O 4) dissociating to nitrogen dioxide (NO 2) will be taken.
Stewart introduced the term "strong ion difference" or [SID] to mean the concentration of strongly dissociating cations minus the concentration of strongly dissociating anions. He characterised this, the total weak acid concentration and the partial pressure of CO 2 as independent variables and formulated a quartic equation relating [H + ] to ...