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Changes in entropy are associated with phase transitions and chemical reactions. Chemical equations make use of the standard molar entropy of reactants and products to find the standard entropy of reaction: [3] = The standard entropy of reaction helps determine whether the reaction will take place spontaneously.
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 ...
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 pure component's molar volume and molar enthalpy are equal to the corresponding partial molar quantities because there is no volume or internal energy change on mixing for an ideal solution. The molar volume of a mixture can be found from the sum of the excess volumes of the components of a mixture:
Flory–Huggins solution theory is a lattice model of the thermodynamics of polymer solutions which takes account of the great dissimilarity in molecular sizes in adapting the usual expression for the entropy of mixing. The result is an equation for the Gibbs free energy change for mixing a polymer with a solvent. Although it makes simplifying ...
The standard state of a material (pure substance, mixture or solution) is a reference point used to calculate its properties under different conditions.A degree sign (°) or a superscript Plimsoll symbol (⦵) is used to designate a thermodynamic quantity in the standard state, such as change in enthalpy (ΔH°), change in entropy (ΔS°), or change in Gibbs free energy (ΔG°).
Data obtained from Lange's Handbook of Chemistry, 10th ed. and CRC Handbook of Chemistry and Physics 44th ed. The annotation, d a°C/b°C, indicates density of solution at temperature a divided by density of pure water at temperature b known as specific gravity. When temperature b is 4 °C, density of water is 0.999972 g/mL.
Standard molar entropy, S o solid? J/(mol K) Heat capacity, c p: 0.212 J/(mol K) at −200°C Liquid properties Std enthalpy change of formation, Δ f H o liquid: −318.2 kJ/mol Standard molar entropy, S o liquid: 180 J/(mol K) Heat capacity, c p: 2.68 J/(gK) at 20°C-25°C Gas properties Std enthalpy change of formation, Δ f H o gas: −261. ...