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  2. Van 't Hoff equation - Wikipedia

    en.wikipedia.org/wiki/Van_'t_Hoff_equation

    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".

  3. Table of thermodynamic equations - Wikipedia

    en.wikipedia.org/wiki/Table_of_thermodynamic...

    R = gas constant; N = number of ... Entropy change ... Thermodynamic equation calculator This page was last edited on 9 December 2024, at 23:05 ...

  4. Entropy - Wikipedia

    en.wikipedia.org/wiki/Entropy

    Since an entropy is a state function, the entropy change of the system for an irreversible path is the same as for a reversible path between the same two states. [22] However, the heat transferred to or from the surroundings is different as well as its entropy change. We can calculate the change of entropy only by integrating the above formula.

  5. Enthalpy–entropy chart - Wikipedia

    en.wikipedia.org/wiki/Enthalpy–entropy_chart

    The Mollier enthalpy–entropy diagram for water and steam. The "dryness fraction", x , gives the fraction by mass of gaseous water in the wet region, the remainder being droplets of liquid. An enthalpy–entropy chart , also known as the H – S chart or Mollier diagram , plots the total heat against entropy, [ 1 ] describing the enthalpy of a ...

  6. Transition state theory - Wikipedia

    en.wikipedia.org/wiki/Transition_state_theory

    Using the Eyring equation, there is a straightforward relationship between ΔG ‡, first-order rate constants, and reaction half-life at a given temperature. 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 ...

  7. Entropy (classical thermodynamics) - Wikipedia

    en.wikipedia.org/wiki/Entropy_(classical...

    In the case of an ideal gas, the heat capacity is constant and the ideal gas law PV = nRT gives that α V V = V/T = nR/p, with n the number of moles and R the molar ideal-gas constant. So, the molar entropy of an ideal gas is given by (,) = (,) + ⁡ ⁡. In this expression C P now is the molar heat capacity. The entropy of inhomogeneous ...

  8. Introduction to entropy - Wikipedia

    en.wikipedia.org/wiki/Introduction_to_entropy

    The entropy of the surrounding room decreases less than the entropy of the ice and water increases: the room temperature of 298 K is larger than 273 K and therefore the ratio, (entropy change), of ⁠ δQ / 298 K ⁠ for the surroundings is smaller than the ratio (entropy change), of ⁠ δQ / 273 K ⁠ for the ice and water system. This is ...

  9. Eyring equation - Wikipedia

    en.wikipedia.org/wiki/Eyring_equation

    The Eyring equation (occasionally also known as Eyring–Polanyi equation) is an equation used in chemical kinetics to describe changes in the rate of a chemical reaction against temperature. It was developed almost simultaneously in 1935 by Henry Eyring , Meredith Gwynne Evans and Michael Polanyi .