According to thermodynamic principles, what is the implication of spontaneous processes in isolated systems?

In thermodynamics, spontaneous processes in isolated systems are characterized by an increase in entropy (dS > 0). This reflects the natural tendency of systems to evolve towards a state of greater disorder. In an isolated system, where no energy or matter can be exchanged with the surroundings, the second law of thermodynamics dictates that the total entropy of the system must increase or remain constant; it cannot decrease.

When a spontaneous process occurs, it signifies that the system is moving towards a more probable and disordered state, resulting in a positive change in entropy. This increase in entropy is fundamental to the spontaneity of processes and indicates that they are energetically favorable without requiring additional energy input from outside the system.

The other options do not accurately represent the implications of spontaneity in isolated systems. A spontaneous process may not necessarily increase the order of the system; in fact, it usually does the opposite. It does not automatically lead to an increase in temperature, as temperature changes depend on the specific process and conditions involved. Moreover, spontaneous processes do not require external energy input; they occur naturally as the system seeks to achieve a state of higher entropy.