What statement is true concerning the internal energy of a substance?

Correct Answer: Option C — The internal potential molecular energy of a substance is a function of the state of matter of the substance, whereas the internal kinetic molecular energy of a substance is a function of the temperature of the substance.

Internal potential energy relates to molecular spacing and state of matter (solid, liquid, gas), while internal kinetic energy is directly proportional to the substance's temperature. Understanding this molecular behavior is essential for analyzing steam properties and refrigerant behavior within shipboard auxiliary systems.