What is a driving force? Name two common and important driving forces, and give an example of each. What is entropy? Although the total energy of the universe is constant, is the entropy of the universe constant? What is a spontaneous process?

Interpretation:

The definition of a driving force, the two common and important driving forces along with their examples and the definition of entropy are to be stated. Whether the entropy of the universe is constant is to be predicted. The spontaneous process is to be stated.

Concept Introduction:

The change in Gibbs free energy, enthalpy and entropy is represented by ΔG°, ΔH° and ΔS° respectively. They are state functions. The relation of ΔG° with ΔH° and ΔS° is shown as,

ΔG°=ΔH°−TΔS°

The change in Gibbs free energy describes the spontaneity of the reaction. The change in enthalpy describes the relative bond strength in the substance, whereas the change in entropy describes the randomness in the system.

The reaction cannot be facilitated and completed without the presence of driving forces. Therefore, the forces which are required to promote and complete the chemical reactions are referred to as driving forces.

The two common and important driving forces are related to change in heat and change in randomness in the chemical reaction. Entropy and enthalpy are used to describe changes in randomness and changes in heat respectively. Therefore, the two common and important driving forces are entropy and enthalpy.

The example of entropy as a driving force is shown below.

H2O(s)+6.01 kJ→H2O(l)

According to second law of thermodynamics, the value of entropy is positive for the spontaneous reactions. The above expression indicates that disorder in a system increases during the conversion of ice into liquid. Ice is more ordered than liquid water. Hence, the driving force in the above reaction is entropy which facilitates the reaction.

Enthalpy gives the information regarding changes in heat or energy during the formation of reactant into products.

The chemical reaction in which energy is released during the formation of products is known as exothermic reactions