Energy per mole

Inspection of Table III-l shows that there is a wide range of surface tension and E values. It is more instructive, however, to compare E values calculated on an energy per mole basis. The area per mole of spherical molecules of molecular weight M and radius r is... 

We would like to know the binding energy per mole of PALA and the enthalpy of the transformation T R, but we do not have enough information. Independent studies show that partial unfolding of ACTase occurs on binding of less PALA, in particular, 1.8 mol of PALA cause 43% unfolding and 4.8 mol... 

Constant in rotational partition function of gases Constant relating wave number and moment of inertia Z = constant relating wave number and energy per mole... 

The Arrhenius equation relates the rate constant k of an elementary reaction to the absolute temperature T R is the gas constant. The parameter is the activation energy, with dimensions of energy per mole, and A is the preexponential factor, which has the units of k. If A is a first-order rate constant, A has the units seconds, so it is sometimes called the frequency factor. 

From Eq. (6-1) it is evident that A has the units of k and that E has the units energy per mole. For many decades the usual units of E were kilocalories per mole, but in the International System of Units (SI) E should be expressed in kilojoules per mole (1 kJ = 4.184 kcal). In order to interpret the extant and future kinetic literature, it is essential to be able to use both of these forms. 

At best, van der Waals interactions are weak and individually contribute 0.4 to 4.0 kj/mol of stabilization energy. ITowever, the sum of many such interactions within a macromolecule or between macromolecules can be substantial. For example, model studies of heats of sublimation show that each methylene group in a crystalline hydrocarbon accounts for 8 k[, and each C—IT group in a benzene crystal contributes 7 k[ of van der Waals energy per mole. Calculations indicate that the attractive van der Waals energy between the enzyme lysozyme and a sugar substrate that it binds is about 60 k[/mol. 

A useful way to approach these individual point defect energies is to define the energy per mole or cohesive energy of perfect material with respect to separated free atoms, Cmoi-We can then arbitrarily divide this between the atoms of type A and B so that ... 

The Conventional Standard Free Energy of Solution. Returning now to the solution of a crystalline solid, let us consider the free energy of solution. Taking a uni-univalent substance let AF denote the change in free energy per mole when additional ions are added to a solution at temperature T where the solute has the mole fraction x and let us fix attention on the quantity... 

In the last step, we have used the relation 1— + f — +. .. = ln2. Finally, we multiply T. by 2 to obtain the total energy arising from interactions on each side of the ion and then by Avogadro s constant, NA, to obtain an expression for the potential energy per mole of ions. The outcome is... 

FIGURE 7.27 The standard Gibbs free energy of formation of a compound is defined as the standard reaction Gibbs free energy per mole of formula units of the compound when the compound is formed from its elements. It represents a "thermodynamic altitude" with respect to the elements at "sea level." The numerical values are in kilojoules per mole. 

Energy Source Content (mmol/kg wet muscle) Energy per Mole (kj) Energy Stored in Body (kJ)... 

For reactions in the gas phase, the free energy per mole of gas as a function of pressure is given... 

The degree of realism of these model structures can be assessed by comparison of computed properties with experimental ones. The cohesive energy is, by definition, the difference in energy per mole of substance between a parent chain in its bulk environment and the same parent chain in vacuo, i.e., when all intermolecular forces are eliminated. This difference is readily computed from the minimized... 

Here, E is the total energy of the system, Ej is the energy per mole of component i, F is the volumetric flow rate, C is the molar concentration and S is the number of components (reactants and inerts). The work term can be separated into flow work and other work Ws, according to... 

This result is identical to that obtained in elementary kinetic theory. There is, in effect a contribution of RT to the energy per mole for each of the three directions in space. Furthermore, this result allows the identification /J = 1 fkTy as suggested earlier. 

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