What is meant by "total energy" in thermodynamics?

In thermodynamics, "total energy" refers to the comprehensive energy content of a system, which includes the sum of its kinetic energy, potential energy, and internal energy. Kinetic energy is associated with the motion of particles within the system, potential energy reflects the position of those particles relative to one another, and internal energy encompasses all forms of energy present at the microscopic level, including both kinetic and potential energies of the molecules, as well as energy associated with their interactions.

This concept is critical because it defines how energy is conserved and transformed within a system during processes such as heat transfer, work done by or on the system, and phase changes. Understanding total energy allows for better predictions of system behavior under various conditions, establishing foundational principles that apply to engines, refrigerators, and various thermodynamic processes.

The other options focus on specific forms or implications of energy rather than providing a holistic view of the energy within a thermodynamic system. Total work, energy changes in states of matter, and chemical bond energy are all relevant in different contexts but do not capture the comprehensive definition of total energy as used in thermodynamics.