How is free energy of reaction calculated?

The calculation of the free energy of a reaction is accurately represented by the equation known as Gibbs Free Energy equation, which is expressed as:

[ \Delta G = \Delta H - T \Delta S ]

In this equation:

• (\Delta G) represents the change in Gibbs free energy.

• (\Delta H) stands for the change in enthalpy.

• (T) is the temperature in Kelvin.

• (\Delta S) denotes the change in entropy.

This relationship illustrates how changes in both the enthalpy and the entropy of a system contribute to the spontaneity of a reaction. The term (-T \Delta S) reflects how the randomness or disorder of a system impacts free energy. If a reaction has a positive change in entropy ((\Delta S > 0)), it can favor spontaneity even if the enthalpy increases.

Thus, the correct answer comprehensively captures the relationship between enthalpy, temperature, and entropy change in determining the free energy of a reaction.