What is internal energy and how is it defined in thermodynamics?

[princejan7]

Wikipedia says its the TOTAL energy contained by a thermodynamic system.

But the textbook says
Total energy = internal energy + kinetic energy + potential energy

 

[Chestermiller]

Wikipedia says its the TOTAL energy contained by a thermodynamic system.

But the textbook says
Total energy = internal energy + kinetic energy + potential energy

Strictly speaking, your textbook is the better, and more common, definition.

 

[ehild]

Read Wikipedia further

In thermodynamics, the internal energy is the total energy contained by a thermodynamic system. It is the energy needed to create the system but excludes the energy to displace the system's surroundings, any energy associated with a move as a whole, or due to external force fields.

ehild