Which statement best describes the difference between heat and thermal energy?

• A. Heat and thermal energy are both forms of energy stored within an object and are always equal.
• B. Thermal energy is the energy transferred between objects, while heat is the energy contained within a substance.
• C. Heat refers to the potential energy of molecules, whereas thermal energy refers to their kinetic energy.
• D. Heat is the transfer of energy between objects due to a temperature difference, while thermal energy is the total kinetic energy of particles within a substance.

Answer: (D)

Verified step by step guidance

1. Understand that thermal energy refers to the total kinetic energy of all the particles in a substance. It depends on both the temperature and the number of particles present.
2. Recognize that heat is not energy contained within an object, but rather energy in transit. Heat is the energy transferred between objects because of a temperature difference.
3. Note that heat flows spontaneously from a hotter object to a cooler one until thermal equilibrium is reached.
4. Distinguish that thermal energy is a state function (depends on the state of the system), while heat is a path function (depends on the process of energy transfer).
5. Summarize that the key difference is: thermal energy is the total internal kinetic energy of particles in a substance, whereas heat is the energy transferred due to temperature difference.