## 11.99

$\Delta G^{\circ}= \Delta H^{\circ} - T \Delta S^{\circ}$

$\Delta G^{\circ}= -RT\ln K$

$\Delta G^{\circ}= \sum \Delta G_{f}^{\circ}(products) - \sum \Delta G_{f}^{\circ}(reactants)$

Wenting Hu 2H
Posts: 33
Joined: Fri Sep 29, 2017 7:06 am

### 11.99

For 11.99,

(a) Calculate the standard Gibbs free energies of
formation of the halogen atoms X(g) at 1000. K from data
available in Table 11.2. (b) Show how these data correlate with
the XOX bond strength by plotting the standard Gibbs free
energy of formation of the atoms against the bond dissociation
energy and atomic number. Rationalize any trends you observe.

Where does the answer book get the bond dissociation energy values? And I am confused about the explanations that the book gives for part b. Why does the F-F bond have a lower energy?

Danah Albaaj 1I
Posts: 50
Joined: Fri Sep 29, 2017 7:07 am

### Re: 11.99

The bond dissociation energies are from a table in Chapter 3. The F-F bond is lower in energy than the other bonds because of its short bond length which in turn causes the electron pairs between the two F atoms to have stronger electron repulsion. This repulsion causes the dissociation energy of the bond to be lower due to the electron pair's on each F atom desire to be away from the other.