Exothermic reaction potential energy diagram

Look carefully at the potential energy diagram. Check that you have labelled it completely. Since the forward reaction is exothermic, the reactants should be at a higher energy level than the products, and they are. The value of afrev) is reasonable. 

Draw and label a potential energy diagram for the following exothermic reaction. Include E, the activated complex, and AH. 

Fig. 11. Potential energy diagram for a hypothetical exothermic reaction, showing the transition state as the saddle point.

For DM ABN in polar solvents, the observed activation energy AB for the backward reaction is larger than BA, that is, the adiabatic photoreaction is exothermic. For example, from the spectra and activation energies shown in Figs. 2.1 and 2.8, the potential energy diagram displayed in Fig. 2.9 can be constructed. Only part of the strong redshift of the A band is... 

Figure 7.1 Potential Energy Diagram for an Exothermic Reaction...

Both exothermic and endothermic reactions are often represented graphically with potential energy diagrams, as seen in Figure l-5b. Maybe you can see why endothermic reactions are sometimes called uphill reactions, as they need energy to be continuously added in order to continue. 

Figure 16-10 A potential energy diagram, (a) A reaction that releases energy (exothermic). An example of an exothermic gas-phase reaction is...

FIGURE 10.5 Potential energy diagram (enthalpy of reaction in kcal/mol) for oxidative addition of thiols. The first step involves the formation of a reversible 19 e coordinated thiol adduct that has an estimated enthalpy of binding of —3 to —6 kcal/mol. The transition state occurs when this is attacked by a second mole of chromium radical. The measured enthalpy of activation is near 0 kcal/mol since the exothermic enthalpy of binding in the first step is canceled by the activation enthalpy of the second step. Adapted with permission from reference 79. Copyright 1996, American Chemical Society. 

Sketch a potential energy diagram for a reaction that shows the effect of a catalyst on an exothermic reaction. 

From our earlier discussions, we know that exothermic reactions release energy and endothermic reactions consume energy. Here, we will plot the potential energy diagrams of exothermic and endothermic reactions. Before we do that, we will discuss the concept of transition state. Consider the hypothetical reaction shown below ... 

The potential-energy diagram for the El reaction (Figure 6-12) is similar to that for the Sn 1 reaction. The ionization step is strongly endothermic, with a rate-limiting transition state. The second step is a fast exothermic deprotonation by a base. The base... 

Figure 3.1 Generic potential energy diagram showing the effect of a catalyst in a hypothetical exothermic chemical reaction X + Y to give Z.

Construct a diagram like that in Figure 16-lOa. (a) Write a generic equation that would have such a potential energy diagram, (b) Is the reaction exothermic or endothermic ... 

Draw a potential-energy diagram for an uncatalyzed exothermic reaction. On the same diagram, indicate the change that results on the addition of a catalyst. Discuss the role of a catalyst in changing the rate of reaction. 

The subsequent activation energies of the surface hydrogenation steps [reactions (5.5), (5.6), and (5.7)] are predetermined by the shape of the reactant and product parts of the potential energy diagram. At the product end of the potential, the overall reaction is exothermic by 46 kJ moP and the desorption activation energy of ammonia from Fe(lll) is 50 kJ moP which is the activation energy for reaction (5.8) (Es.g) of Table 5.1. 

Figure 3-8 Potential-energy diagrams (left) the reaction of a fluorine atom with CH4, an exothermic process with an early transition state and (right) the reaction of an iodine atom with CH4, an endothermic transformation with a late transition state. Both are thus in accord with the Hammond postulate.

Figure 15-20 Potential-energy diagram describing the course of the reaction of benzene with an electrophile. The first transition state is rate determining. Proton loss is relatively fast. The overall rate of the reaction is controlled by EaJ the amount of exothermic energy released is given by AH°.

The potential energy surface [47] for this reaction (Fig. 5) shows many potentially competitive pathways, labeled A-F, leading to the two most exothermic product channels. Many of these pathways can be isotopically separated by reaction of 02 with HCCO in normal abundance, as diagramed in Fig. 5. Zou and Osbom used time-resolved Fourier transform emission spectroscopy to detect the CO and CO2 products of this reaction [47]. Rotationally resolved infrared (IR) spectroscopy can easily identify all the possible isotopologs. For example. Fig. 6 shows a single... 

The energy diagram above details exothermic reactions, where the total potential energy of products is smaller than that of reactants . 

---