版权所有：华东理工大学物理化学教研室 5 The initial state of the system is i and in this state the internal energy is Ui. Work is done by the system as it expands adiabatically to a state f. In this state the system has an internal energy Uf and the work done on the system as it changes along Path 1 from i to f is w. U is a property of the state; w is a p r o p e r t y o f the path. 3.1 State functions 1). Exact and inexact differential ∫ Δ = f i U d U版权所有：华东理工大学物理化学教研室 5 The initial state of the system is i and in this state the internal energy is Ui. Work is done by the system as it expands adiabatically to a state f. In this state the system has an internal energy Uf and the work done on the system as it changes along Path 1 from i to f is w. U is a property of the state; w is a p r o p e r t y o f the path. 3.1 State functions 1). Exact and inexact differential ∫ Δ = f i U d U