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  2. 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.

  3. 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".

  4. 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 ...

  5. 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 ...

  6. Boltzmann's entropy formula - Wikipedia

    en.wikipedia.org/wiki/Boltzmann's_entropy_formula

    Boltzmann's equation—carved on his gravestone. [1]In statistical mechanics, Boltzmann's equation (also known as the Boltzmann–Planck equation) is a probability equation relating the entropy, also written as , of an ideal gas to the multiplicity (commonly denoted as or ), the number of real microstates corresponding to the gas's macrostate:

  7. 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 ...

  8. Trouton's rule - Wikipedia

    en.wikipedia.org/wiki/Trouton's_rule

    Trouton’s rule can be explained by using Boltzmann's definition of entropy to the relative change in free volume (that is, space available for movement) between the liquid and vapour phases. [ 2 ] [ 3 ] It is valid for many liquids; for instance, the entropy of vaporization of toluene is 87.30 J/(K·mol), that of benzene is 89.45 J/(K·mol ...

  9. Second law of thermodynamics - Wikipedia

    en.wikipedia.org/wiki/Second_law_of_thermodynamics

    This is possible provided the total entropy change of the system plus the surroundings is positive as required by the second law: ΔS tot = ΔS + ΔS R > 0. For the three examples given above: 1) Heat can be transferred from a region of lower temperature to a higher temperature in a refrigerator or in a heat pump. These machines must provide ...