Introduction:
The second law of thermodynamics is a fundamental principle in physics that deals with the concept of entropy. Entropy is a measure of the disorder or randomness of a system, and the second law states that the entropy of an isolated system will always increase over time.

Explanation:
When considering any process, whether it be a chemical reaction, a physical change, or any other transformation, the second law of thermodynamics requires that the change in entropy of the universe be positive or zero. This can be understood through the following points:

1. Change in Entropy:
The entropy of a system can either increase or decrease during a process. If the system becomes more disordered or random, the entropy increases, and if it becomes more ordered or organized, the entropy decreases. The change in entropy of the system is denoted as ΔS.

2. Entropy of the Universe:
The universe is considered as a closed system, meaning that it does not exchange matter or energy with its surroundings. Therefore, the entropy change of the universe (ΔSuniverse) is the sum of the entropy change of the system (ΔSsystem) and the surroundings (ΔSsurroundings).

3. Positive Entropy Change:
According to the second law of thermodynamics, the entropy of the universe must increase or remain constant for any spontaneous process. This implies that if the entropy of the system decreases (ΔSsystem < 0),="" the="" entropy="" of="" the="" surroundings="" must="" increase="" (δssurroundings="" /> 0) to compensate and ensure that the total entropy change of the universe (ΔSuniverse) is positive. Therefore, a positive change in entropy of the universe is required.

4. Zero Entropy Change:
In some special cases, a process may occur with no change in entropy of the system (ΔSsystem = 0). In such situations, the entropy change of the surroundings (ΔSsurroundings) must be equal to zero as well to maintain a zero change in entropy of the universe (ΔSuniverse = 0). This can occur when there is a perfect balance or symmetry between the system and its surroundings.

Conclusion:
In summary, the second law of thermodynamics requires that the change in entropy of the universe be positive or zero for any process. A positive entropy change indicates an increase in disorder or randomness, while a zero entropy change implies a balance between the system and its surroundings. This law plays a crucial role in understanding the direction and feasibility of physical and chemical processes.