6. Thermodynamics and Kinetics

For the following acid–base reaction, (d) calculate ∆G° at 298 K.

For the following acid–base reaction, (e) calculate ∆G° at 273 K.

For the following acid–base reaction, (f) calculate ∆G° at 373 K.

For each of the following acid–base reactions, (iii) calculate ∆G°. If a pK_a is not one of the ten common ones we learned in Chapter 4, it will be given to you.

(a)

Using the bond-dissociation energies in Table 5.6 (see Section 5.3.1), estimate the equilibrium constant of the following reaction at 298 K.

For the following reactions we have not seen yet, which side, if either, would be favored by increasing the temperature?

(c)

For the following reactions we have not seen yet, which side, if either, would be favored by increasing the temperature?

(d)

For the following equilibrium processes and the corresponding ∆G°, calculate (i) K_eq and (ii) the % composition of the equilibrium mixture (% reactants, % products) at 298 K.

(a)

For the following equilibrium processes and the corresponding ∆G°, calculate (i) K_eq and (ii) the % composition of the equilibrium mixture (% reactants, % products) at 298 K.

(b)

For each pair of reactions, predict which will happen more quickly.

[For (a) and (b), think about the stability of the bases involved.]

(a)

For the following equilibrium processes and the corresponding ∆G° , indicate whether you expect the equilibrium constant to be greater than, equal to, or less than 1. Justify your expectation in words.

(b)

For the following acid–base reactions studied in Assessment 5.25, draw a likely transition state. Be sure to indicate in your drawing the degree to which bonds are broken or formed.

(a)

For the following acid–base reactions studied in Assessment 5.25, draw a likely transition state. Be sure to indicate in your drawing the degree to which bonds are broken or formed.

(c) H₃O⁺ + Br^– ⇌ H₂O + HBr

For the following acid–base reactions studied in Assessment 5.25, draw a likely transition state. Be sure to indicate in your drawing the degree to which bonds are broken or formed.

(b)

Calculate ∆G° for the conversion of “axial” methylcyclohexane to “equatorial” methylcyclohexane at 25 °C.