List the characteristics of internal energy.

Answer

Characteristics of internal energy (U):
The internal energy of a system is an extensive property.
The internal energy of a system is a state function.
The change in internal energy of a system is expressed as `DeltaU-U_(f)-U_(i)`
in a cyclic process, there is no internal energy change. ` DeltaU_("cyclic") = 0 `
If the internal energy of the system in the final state `(U_(f))` is less than the internal energy of the system in its initial state `(U_(i)) , "then" Delta U` would be negative.
` Delta U = U_(f) - U_(i) = - ve(U_(f)lt U_(i))`
If the internal energy of the system in hte final state `(U_(f))` is greater than the internal energy of the system in its initial state `(U_(i)) "then" DeltaU` would be positive.
`Delta U = U_(f) - U_(i) = + ve (U_(f)gt U_(i))`