What does the second law of thermodynamics state regarding spontaneous processes?

The second law of thermodynamics specifically states that for any spontaneous process, the total entropy of the universe must increase. This principle reflects the natural tendency of systems to evolve toward thermodynamic equilibrium, characterized by maximum entropy. In spontaneous processes, the system moves from a state of lower entropy to a higher entropy state, which contributes to the total entropy change when considering both the system and its surroundings.

For instance, when ice melts in a warm environment, the entropy of the water (system) increases significantly as the structured solid ice converts into a less ordered liquid state. Simultaneously, the entropy of the surroundings increases as thermal energy is transferred to the ice. The resulting net change in entropy for the universe (system plus surroundings) is positive, affirming the second law.

The other options do not accurately capture the essence of the second law. A spontaneous process does not necessarily increase the energy of the system; it may actually result in energy being released or transformed. Moreover, spontaneous processes are characterized by a change in entropy, rather than proceeding with zero change. Finally, while work can be required in some processes, it is not a universal requirement for spontaneity as spontaneous processes can occur without external work input.