6. Thermodynamics and Kinetics

Use bond-dissociation enthalpies (Table 4-2, p. 167) to calculate values of ΔH° for the following reactions.

c. (CH₃)₃C—OH + HCl → (CH₃)₃C—Cl + H₂O

Use bond-dissociation enthalpies (Table 4-2, p. 167) to calculate values of ΔH° for the following reactions.

d. CH₃CH₂CH₃ + H₂ → CH₃CH₃ + CH₄

If the following reaction is favorable, what can we say about the sign of ∆H°? Explain your answer.

Give the approximate bond-dissociation energy for each indicated bond.

Calculate ∆H° for the following alkene addition reaction, one we discuss further in Chapter 7. Predict the sign of ∆S° . (The BDE for C―C π bond is approximately 65 kcal/mol.)

Reaction (c), on the other hand, is favored (∆G° < 0). Identify the bonds formed and broken and explain this result in light of (a) and (b).

(c)

Calculate ∆H° for the following equilibrium processes.

(b)

The combustion of alkanes is exothermic (∆H° < 0) . Would you expect the combustion of butane or cyclobutane to be more exothermic?

Reactions (a) and (b) are disfavored overall (∆G° > 0), yet they are favored based on ∆H°. Identify the bonds formed and broken for (a) and (b).

(b)

(i) Using bond dissociation energies, calculate ∆H° for the following reactions. [BDE for O―H = 110 kcal /mol.]

(b)

(a) Using bond-dissociation energies (Table 5.6), which of the indicated bonds should break most easily?

(b) How does that help you explain the results shown in Figure 11.40?

Given that ∆H° for the reaction is -42 kcal/mol and the bond dissociation enthalpies for the C−H, C−Cl, and O−H bonds are 101, 85, and 105 kcal/mol respectively, calculate the bond dissociation enthalpy of the O−Cl bond.

Calculate ∆H° for the following reactions.

(b) CH₃Br + HCl → CH₃Cl + HBr

Calculate ∆H° for the following reactions.

(c) CH₃CH₃ + HOOH → CH₃CH₂OH + H₂O

Calculate ∆H° for the following reactions.

(a)