Question

List the characteristics of internal energy.

Answer 1

• The internal energy of a system is an extensive property. It depends on the number of substances present in the system.
• The internal energy of a system is a state function. It depends only upon the state variables (T, P, V. n) of the system.
• The change in internal energy is as ∆U = U₂ – U₁
• In a cyclic process, there is no energy change. `∆"U"_"(cyclic)"` = 0.
• If the internal energy of the system at the final state (U_f) is less than the internal energy of the system at its initial state (U_i), then ∆U would be negative.
• if U_f < U_i ∆U = U_f – U_i = −ve
• if U_f > U_i ∆U = U_f – U_i = +ve