Negative free energy

FIG. 22-40 Normalized free-energy difference between distributed (II) and nondistributed (I) states of tbe solid particles versus tbree-pbase contact angle (collection at tbe interface is not considered). A negative free-energy difference implies tbat tbe distributed state is preferred over tbe nondistributed state. Note especially tbe significant effect of n, tbe ratio of tbe liquid droplet to solid-particle radius. [From Jacques, Ho-oaron ura, and Hemy, Am. Inst. Cbem. Eng. J., 25 1), 160 (1979).]... 

There seem to be no large-scale uses for HI outside the laboratory, where it is used in various iodination reactions (lecture bottles containing 400 g HI are available). Commercial solutions contain 40-55 wt% of HI (cf. azeotrope at 56.9% HI, p. 815) and these solutions are thermodynamically much more stable than pure HI as indicated by the large negative free energy of solution. 

Elastomer blends in which the components react (reactive blending) with each other provide the best route to obtain a homogeneous product with improved physicals. The negative free energy... 

Thermodynamically, intermixing as above arises from achieving a negative free energy from the process in mm, this arises by balancing a contribution from enthalpy (heat content) with another from entropy (involving material stmctural aspects). The solubility parameter reflects the enthalpic term. 

A coupled process links a spontaneous reaction with a nonspontaneous one. In this case, the negative free energy change of the acetyl phosphate reaction drives the conversion of ADP to ATP. 

A reaction that proceeds with a negative free-energy change is exergonic. 

To calculate the reaction s equilibrium constant, we note that the free energy change A Gsw of each of the swap reactions in Equation 11.1 is the negative free energy of formation from the elements of the corresponding species... 

The thermodynamic drive for each reaction is its negative free energy change, —AGr. From Equation 7.15, this quantity is given as,... 

Fig. 22.7. Thermodynamic driving forces for various anaerobic (top) and aerobic (bottom) microbial metabolisms during mixing of a subsea hydrothermal fluid with seawater, as a function of temperature. Since the driving force is the negative free energy change of reaction, metabolisms with positive drives are favored thermodynamically those with negative drives cannot proceed. The drive for sulfide oxidation is the mirror image of that for hydrogentrophic sulfate reduction, since in the calculation 02(aq) and H2(aq) are in equilibrium.

Inherent instability, which can manifest itself by a unimolecular rearrangement to a form which has a more negative free energy of formation, e.g., the isomerisation of a secondary to a tertiary cation or to an allylic cation. 

D—If the reaction occurs readily, it must be spontaneous. Spontaneous reactions require AG° < 0. A negative free energy leads to a large K(> 1). 

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