Potential energy change

Consider the thermodynamic process in the fan (Fig. 9.33). As the fan is a stationary flow system, consideration is directed to the total enthalpy change. As the suction openings are often at the same, or almost the same level, the potential energy change can be neglected. 

Quite similar equations can be formulated for AG and AH by use of the partition function f of the activated complex. It follows from equations (6) and (7) that AEp can only be evaluated if the partition functions and AEz are available from spectroscopic data or heat capacity measurements. However, if AG = AH, the entropy change AS equals zero, and if AEz also equal to zero, either AG or AH can then be identified with the potential energy change. If... 

The perturbation process can be quantified using distribution functions of the potential energy change AU (for FEP) or work W (for NEW). The procedure is the same for both the FEP and NEW calculations, thus we use the term perturbation and the notation x to unify both. 

If there is no shaft work done on the fluid in this system and the elevation (potential energy) change can be neglected, Eq. (9-14) can be rewritten using Eq. (9-13) as follows ... 

Figure 4.7 Potential energy changes that accompany rotation of groups about the carbon-carbon bond of ethane.

Figure 4 Potential energy change at a metal surface.

Numerical Solution for Orifice Flow With orifice flow, the last two terms of the momentum balance (line resistance and potential energy change) are negligible. The momentum balance, Eq. (23-40), reduces to... 

Fig. 10.3 Potential energy changes during rotation about C—C single bond of ethane.

As rAB oo, A is separated from BC and V = VBC. As rBC —> < , C is separated from AB and V = yBC. As the reaction proceeds, the potential energy changes from BC to AB. As the reactants approach each other, there is some repulsion leading to a maximum barrier when the three atoms are simultaneously closed to each other. Subsequently, there is a drop in the potential leading to the separation of the products. The maximum point is called the saddle point. 

Another way of visualising the potential energy of a molecular system is in terms of the potential-energy changes that occur during a chemical reaction. This is represented by means of a reaction profile where the potential energy values of the reactants, products, transition states and intermediates are plotted against the reaction coordinate (the lowest... 

Neglecting kinetic and potential energy changes, a steady state and steady flow mass and energy balance on the components of the Braysson cycle have the general forms ... 

FIGURE 2.7 (a) potential energy profile illustrating the potential energy changes associated with rotation around a C-C bond of ethane (b) Newman projections of designated conformers of n-butane. 

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