Sum of all the microscopic forms of E.
Sum of all Kinetic and Potential Energies of the molecules of a system.
U (or E)
Hyper Physics link
Does not include translation or rotation of body as a whole.
Cannot measure total. Can only measure ΔU
First Law Statements:
- A thermodynamic system can store or hold energy. This Internal Energy is conserved.
- The internal energy of the universe is constant.
- The change in the internal energy of the universe is zero.
ΔUuniverse = 0
- The sum of energy changes in the system and surroundings is zero.
ΔUuniverse = ΔUsystem + ΔUsurroundings = 0
- For an isolated system: ΔUsystem = 0
- For a closed system: ΔUsystem = q + w
- For a closed system at constant volume with only PV work:
ΔUsystem = qv