Answer:
Gibbs free-energy of the reaction = (–12.5 kJ/mol)
Explanation:
The Gibbs free-energy of a reaction predicts the spontaneity or feasibility of a given chemical reaction.
Given the standard Gibbs free energy changes:
Phosphocreatine → creatine + Pi, ∆G° = –43.0 kJ/mol ...(1)
ATP → ADP + Pi , ∆G° = –30.5 kJ/mol ....(2)
Now to calculate the Gibbs free-energy of the given chemical reaction: Phosphocreatine + ADP → creatine + ATP; the equation (2) is reversed to give:
ADP + Pi → ATP, ∆G° = + 30.5 kJ/mol ...(3)
Now the equation (3) and (1) are added, to give:
Phosphocreatine + ADP + Pi→ creatine + ATP + Pi
⇒ Phosphocreatine + ADP → creatine + ATP
Therefore, to calculate the Gibbs free-energy of the reaction, the standard Gibbs free energy changes of the equations (1) and (3) are added similarly:
Gibbs free-energy of the reaction: ∆G° = (–43.0 kJ/mol) + ( + 30.5 kJ/mol) = (–12.5 kJ/mol)
Therefore, the Gibbs free-energy of the reaction = (–12.5 kJ/mol)
