Question

Define internal energy of a system. Is it a state variable or not? What is the nature of the internal energy of an ideal gas?

Answer 1

Internal Energy and the State of a System The state of a system refers to the quintessential properties fully define a system’s characteristics. Internal energy U is part of the description of the state of a system – the energy it has by just sitting there, not macroscopically moving. Its main constituents are: C Random motions of atomic particles (temperature) C Interatomic and intermolecular potential energies State variables are the quantities that specify the essential internal state of a system: C Temperature C Pressure C Volume C Phase or internal structure (gaseous, crystalline, etc.)