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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. 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 ...

  4. 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".

  5. Temperature–entropy diagram - Wikipedia

    en.wikipedia.org/wiki/Temperature–entropy_diagram

    In thermodynamics, a temperature–entropy (T–s) diagram is a thermodynamic diagram used to visualize changes to temperature (T ) and specific entropy (s) during a thermodynamic process or cycle as the graph of a curve. It is a useful and common tool, particularly because it helps to visualize the heat transfer during a process.

  6. Thermodynamic databases for pure substances - Wikipedia

    en.wikipedia.org/wiki/Thermodynamic_databases...

    Absolute entropy of strontium. The solid line refers to the entropy of strontium in its normal standard state at 1 atm pressure. The dashed line refers to the entropy of strontium vapor in a non-physical state. The standard entropy change for the formation of a compound from the elements, or for any standard reaction is designated ΔS° form or ...

  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. 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 ...

  9. Thermodynamic cycle - Wikipedia

    en.wikipedia.org/wiki/Thermodynamic_cycle

    Whether carried out reversible or irreversibly, the net entropy change of the system is zero, as entropy is a state function. During a closed cycle, the system returns to its original thermodynamic state of temperature and pressure. Process quantities (or path quantities), such as heat and work are process dependent.