To Predict Whether Pairs of Coupled Reactions Will Proceed Spontaneously

Question

To predict whether pairs of coupled reactions will proceed spontaneously:
A) Subtract the smaller from the larger ΔG.
B) Sum the ΔG°′ values for each reaction.
C) Add the ΔS values for each reaction at constant temperature.
D) The absolute value of the positive ΔG°′ must be larger than the value of the negative ΔG°′.
E) None are true.

Accepted Answer

To predict whether pairs of coupled reactions will proceed spontaneously, you sum the ΔG°′ values for each reaction. The overall spontaneity of the coupled reactions is determined by the sign of the sum of their ΔG°′ values. If the sum is negative, the coupled reactions are spontaneous under standard conditions.