Which statement correctly describes the change in entropy, ΔS(system), when it is positive?

When the change in entropy, ΔS(system), is positive, it indicates an increase in the disorder of the system. Entropy is a measure of the randomness or disorder within a system, and a positive change signifies that the system has transitioned to a state with a higher level of disorder or a greater number of accessible microstates. This is often observed in processes such as melting, vaporization, or any reactions where gaseous products are formed from solid or liquid reactants.

The concept of entropy is crucial in understanding the tendency of natural processes since systems tend to evolve toward states of higher entropy over time. For instance, when a solid melts into a liquid, the structure becomes more disordered, resulting in a higher entropy state. Similarly, during a gas expansion, the molecules spread out and occupy a larger volume, leading to increased disorder and thus a positive change in entropy.

While energy absorption and temperature changes can be associated with entropy changes, they do not directly define the increase in disorder that characterizes a positive ΔS. Understanding this connectivity between entropy and disorder helps in analyzing chemical reactions and physical processes from a thermodynamic perspective.