What does internal energy represent in a system?

Internal energy is a key concept in thermodynamics and refers to the total energy contained within a system. It reflects the energy associated with the motion and position of all particles that make up the system. Specifically, internal energy incorporates both kinetic energy, which relates to the motion of the particles, and potential energy, which is associated with the positional relationships between particles, such as intermolecular forces.

In a thermodynamic context, kinetic energy encompasses the random motion of molecules, including translation, rotation, and vibration. Meanwhile, potential energy accounts for the forces between the particles, such as attractive or repulsive forces that can exist due to chemical bonds and other interactions.

Thus, the concept of internal energy is best represented as the sum of these two types of energy. This makes it a comprehensive measure of a system’s energy state, encompassing both the energy due to particle motion and the configuration of these particles relative to one another.

Other options focus on singling out either kinetic energy or potential energy, which do not capture the entirety of internal energy. Additionally, mentioning energy associated with a chemical reaction is specific to certain processes and does not encompass the broader definition of internal energy. Therefore, recognizing internal energy as the total of both kinetic and potential energies accurately describes its