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Free Steam Tables Online calculator based on IAPWS-IF97; FACT-Web programs Various on-line tools for obtaining thermodynamic data and making equilibrium calculations. Mol-Instincts A chemical database based on Quantum Mechanics and QSPR, providing thermodynamic properties for millions of compounds.
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".
Equilibrium constants are determined in order to quantify chemical equilibria.When an equilibrium constant K is expressed as a concentration quotient, = [] [] [] [] it is implied that the activity quotient is constant.
In order to flatten the steep learning curve aqion provides an introduction to fundamental water-related topics in form of a "chemical pocket calculator". Second. The program mediates between two terminological concepts: The calculations are performed in the "scientific realm" of thermodynamics (activities, speciation, log K values, ionic ...
The equilibrium constant of a chemical reaction is the value of its reaction quotient at chemical equilibrium, a state approached by a dynamic chemical system after sufficient time has elapsed at which its composition has no measurable tendency towards further change. For a given set of reaction conditions, the equilibrium constant is ...
In physical organic chemistry, a free-energy relationship or Gibbs energy relation relates the logarithm of a reaction rate constant or equilibrium constant for one series of chemical reactions with the logarithm of the rate or equilibrium constant for a related series of reactions. [1]
A quantity in square brackets, [X], represents the concentration of the chemical substance X. It is understood that the symbol H + stands for the hydrated hydronium ion. K a is an acid dissociation constant. The Henderson–Hasselbalch equation can be applied to a polybasic acid only if its consecutive pK values differ by at least 3.
At 298 K, a reaction with ΔG ‡ = 23 kcal/mol has a rate constant of k ≈ 8.4 × 10 −5 s −1 and a half life of t 1/2 ≈ 2.3 hours, figures that are often rounded to k ~ 10 −4 s −1 and t 1/2 ~ 2 h. Thus, a free energy of activation of this magnitude corresponds to a typical reaction that proceeds to completion overnight at room ...