The free energy change combines the enthalpy change and the entropy change together, along with the temperature, to produce a quantity that can be used to determine if a process is spontaneous or not. For that you need to determine the change in the free energy. But like enthalpy, changes in entropy alone cannot be used to predict whether an overall change is spontaneous. When a change entropy is positive, it makes the change more spontaneous (favorable). Entropy is a measure of disorder when a system become more disordered, the change in entropy is positive. There is another factor that must be considered and that is the entropy.
While a decrease in the enthalpy makes a process more spontaneous (favorable), the change in enthalpy alone cannot be used to predict whether an overall change is spontaneous.
When heat is released, the change in the enthalpy for the system that is releasing the heat decreases, whereas when heat is absorbed, the change in the enthalpy increases. Spontaneous changes are ones in which the free energy of a system decreases.
