Question

In a reaction in which reactant A is in equilibrium with product B at

25 °C, what relative amounts of A and B are present at equilibrium if ΔG° at 25 °C is

a. 2.72 kcal/mol?

b. 0.65 kcal/mol?

c. -2.72 kcal/mol?

d. -0.65 kcal/mol?

Short answer

a. The relative amount of A and B are 1 and 0.01 respectively.

b. The relative amount of A and B are 1 and 0.33 respectively.

c. The relative amount of A and B are 1 and 90 respectively.

d. The relative amount of A and B are 1 and 2.97 respectively.

Step-by-step solution

Explanation of formula

In an equilibrium reaction,

k₁

A ⇌ B

k_-1

From this, we can say, and the relation between k_equi and ΔG^° is equal to

ΔG^° = -RTln(k_equi)

calculation

1. whenΔG^° = 2.72 kcal/mol,

2.72 kcal/mol = -1.987 x 298 x In ( k_equi )

In k_equi =

The relative amount of A and B are 1 and 0.01 respectively.

b. when ΔG^° = 0.65 kcal/mol,

0.65 kcal/mol = -1.987 x 298 x In(k_equi )

The relative amount of A and B are 1 and 0.33 respectively.

1. whenΔG^° = -2.72 kcal/mol,

The relative amount of A and B are 1 and 90 respectively.

1. whenΔG^° = -0.65 kcal/mol,

The relative amount of A and B are 1 and 2.97 respectively.