Final answer:
Whether the change in entropy (ΔS) increases or decreases depends on the process. In a spontaneous process, entropy typically increases, while in a reversible process, entropy remains constant. The second law of thermodynamics dictates that entropy either stays the same or increases.
Step-by-step explanation:
When discussing the entropy (ΔS) of a system, it's important to understand that entropy is a measure of the disorder or randomness in a system. If the entropy of a system is greater, it means that there is more disorder and a higher number of microstates. Now, whether the change in entropy increases or decreases depends on the process the system undergoes.
In general, during a spontaneous process, the entropy of the universe increases. For a given substance, entropy can vary with its phase; for example, solid (Ссolid) has lower entropy than liquid (Сусquid), which in turn has lower entropy than gas (Ссas). Additionally, entropy increases when a system is heated or when solutions are formed.
Specific to processes, if a process is irreversible, entropy always increases. In contrast, for a reversible process, the entropy of the system remains constant. Considering heat transfer, if heat is transferred from a hot object to a cold object, the decrease in entropy of the hot object is always less than the increase in entropy of the cold object, resulting in an overall increase in entropy.
In summary, the second law of thermodynamics states that entropy either remains constant or increases for any process. This is due to the vast number of microstates that exist in systems with greater entropy. The change in entropy (ΔS) thus either stays the same (for reversible processes) or becomes greater (for irreversible processes).