Which factor can lead to an increase in ΔS(system)?

The increase in entropy (ΔS) of a system is often associated with the degree of disorder or randomness in that system. When we consider the formation of gases from solids or liquids, we see a significant increase in disorder. Gases have much greater freedom of movement compared to solids or liquids due to the considerable distances between gas molecules and their ability to occupy larger volumes and move independently.

When a solid or liquid transitions into a gaseous state, the number of accessible microstates — a concept that quantifies the arrangements of particles — increases dramatically. Thus, the transformation from a more ordered phase (solid or liquid) to a less ordered phase (gas) reflects a substantial increase in entropy. This aligns with the second law of thermodynamics, which states that the entropy of an isolated system will tend to increase over time, particularly during spontaneous processes where substances change from a more ordered to a more disordered state.

Other factors mentioned in the question, such as a decrease in temperature, typically result in a decrease in entropy because lower temperatures mean that particle motion slows down, leading to a more ordered state. An increase in pressure generally compresses gases, leading to fewer available microstates and reduced entropy in that scenario. Reduction in molecular complexity, such as simplifying